429 lines
16 KiB
Plaintext
429 lines
16 KiB
Plaintext
/*=============================================================================
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This file is part of FLINT.
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FLINT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FLINT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FLINT; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2011 Fredrik Johansson
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******************************************************************************/
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*******************************************************************************
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Memory management
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*******************************************************************************
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void fmpq_mat_init(fmpq_mat_t mat, slong rows, slong cols)
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Initialises a matrix with the given number of rows and columns for use.
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void fmpq_mat_clear(fmpq_mat_t mat)
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Frees all memory associated with the matrix. The matrix must be
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reinitialised if it is to be used again.
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*******************************************************************************
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Entry access
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*******************************************************************************
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MACRO fmpq_mat_entry(mat,i,j)
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Gives a reference to the entry at row \code{i} and column \code{j}.
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The reference can be passed as an input or output variable to any
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\code{fmpq} function for direct manipulation of the matrix element.
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No bounds checking is performed.
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MACRO fmpq_mat_entry_num(mat,i,j)
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Gives a reference to the numerator of the entry at row \code{i} and
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column \code{j}. The reference can be passed as an input or output
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variable to any \code{fmpz} function for direct manipulation of the
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matrix element. No bounds checking is performed.
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MACRO fmpq_mat_entry_den(mat,i,j)
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Gives a reference to the denominator of the entry at row \code{i} and
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column \code{j}. The reference can be passed as an input or output
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variable to any \code{fmpz} function for direct manipulation of the
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matrix element. No bounds checking is performed.
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*******************************************************************************
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Basic assignment
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*******************************************************************************
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void fmpq_mat_set(fmpq_mat_t dest, const fmpq_mat_t src)
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Sets the entries in \code{dest} to the same values as in \code{src},
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assuming the two matrices have the same dimensions.
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void fmpq_mat_zero(fmpq_mat_t mat)
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Sets \code{mat} to the zero matrix.
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void fmpq_mat_one(fmpq_mat_t mat)
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Let $m$ be the minimum of the number of rows and columns
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in the matrix \code{mat}. This function sets the first
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$m \times m$ block to the identity matrix, and the remaining
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block to zero.
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void fmpq_mat_transpose(fmpq_mat_t rop, const fmpq_mat_t op)
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Sets the matrix \code{rop} to the tranpose of the matrix \code{op},
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assuming that their dimensios are compatible.
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*******************************************************************************
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Addition, scalar multiplication
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*******************************************************************************
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void fmpq_mat_add(fmpq_mat_t mat,
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const fmpq_mat_t mat1, const fmpq_mat_t mat2)
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Sets \code{mat} to the sum of \code{mat1} and \code{mat2},
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assuming that all three matrices have the same dimensions.
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void fmpq_mat_sub(fmpq_mat_t mat,
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const fmpq_mat_t mat1, const fmpq_mat_t mat2)
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Sets \code{mat} to the difference of \code{mat1} and \code{mat2},
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assuming that all three matrices have the same dimensions.
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void fmpq_mat_neg(fmpq_mat_t rop, const fmpq_mat_t op)
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Sets \code{rop} to the negative of \code{op}, assuming that
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the two matrices have the same dimensions.
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void fmpq_mat_scalar_mul_fmpz(fmpq_mat_t rop,
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const fmpq_mat_t op, const fmpz_t x)
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Sets \code{rop} to \code{op} multiplied by the integer $x$,
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assuming that the two matrices have the same dimensions.
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Note that the integer $x$ may not be aliased with any part of
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the entries of \code{rop}.
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void fmpq_mat_scalar_div_fmpz(fmpq_mat_t rop,
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const fmpq_mat_t op, const fmpz_t x)
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Sets \code{rop} to \code{op} divided by the integer $x$,
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assuming that the two matrices have the same dimensions
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and that $x$ is non-zero.
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Note that the integer $x$ may not be aliased with any part of
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the entries of \code{rop}.
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*******************************************************************************
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Input and output
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*******************************************************************************
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void fmpq_mat_print(const fmpq_mat_t mat)
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Prints the matrix \code{mat} to standard output.
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*******************************************************************************
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Random matrix generation
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*******************************************************************************
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void fmpq_mat_randbits(fmpq_mat_t mat, flint_rand_t state, mp_bitcnt_t bits)
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This is equivalent to applying \code{fmpq_randbits} to all entries
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in the matrix.
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void fmpq_mat_randtest(fmpq_mat_t mat, flint_rand_t state, mp_bitcnt_t bits)
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This is equivalent to applying \code{fmpq_randtest} to all entries
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in the matrix.
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*******************************************************************************
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Special matrices
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*******************************************************************************
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void fmpq_mat_hilbert_matrix(fmpq_mat_t mat)
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Sets \code{mat} to a Hilbert matrix of the given size. That is,
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the entry at row $i$ and column $j$ is set to $1/(i+j+1)$.
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*******************************************************************************
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Basic comparison and properties
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*******************************************************************************
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int fmpq_mat_equal(const fmpq_mat_t mat1, const fmpq_mat_t mat2)
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Returns nonzero if \code{mat1} and \code{mat2} have the same shape and
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all their entries agree, and returns zero otherwise. Assumes the
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entries in both \code{mat1} and \code{mat2} are in canonical form.
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int fmpq_mat_is_integral(const fmpq_mat_t mat)
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Returns nonzero if all entries in \code{mat} are integer-valued, and
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returns zero otherwise. Assumes that the entries in \code{mat}
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are in canonical form.
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int fmpq_mat_is_zero(const fmpq_mat_t mat)
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Returns nonzero if all entries in \code{mat} are zero, and returns
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zero otherwise.
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int fmpq_mat_is_empty(const fmpq_mat_t mat)
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Returns a non-zero value if the number of rows or the number of
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columns in \code{mat} is zero, and otherwise returns
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zero.
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int fmpq_mat_is_square(const fmpq_mat_t mat)
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Returns a non-zero value if the number of rows is equal to the
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number of columns in \code{mat}, and otherwise returns zero.
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*******************************************************************************
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Integer matrix conversion
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*******************************************************************************
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int fmpq_mat_get_fmpz_mat(fmpz_mat_t dest, const fmpq_mat_t mat)
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Sets \code{dest} to \code{mat} and returns nonzero if all entries
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in \code{mat} are integer-valued. If not all entries in \code{mat}
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are integer-valued, sets \code{dest} to an undefined matrix
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and returns zero. Assumes that the entries in \code{mat} are
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in canonical form.
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void fmpq_mat_get_fmpz_mat_entrywise(fmpz_mat_t num, fmpz_mat_t den,
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const fmpq_mat_t mat)
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Sets the integer matrices \code{num} and \code{den} respectively
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to the numerators and denominators of the entries in \code{mat}.
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void fmpq_mat_get_fmpz_mat_matwise(fmpz_mat_t num, fmpz_t den,
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const fmpq_mat_t mat)
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Converts all entries in \code{mat} to a common denominator,
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storing the rescaled numerators in \code{num} and the
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denominator in \code{den}. The denominator will be minimal
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if the entries in \code{mat} are in canonical form.
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void fmpq_mat_get_fmpz_mat_rowwise(fmpz_mat_t num, fmpz * den,
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const fmpq_mat_t mat)
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Clears denominators in \code{mat} row by row. The rescaled
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numerators are written to \code{num}, and the denominator
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of row \code{i} is written to position \code{i} in \code{den}
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which can be a preinitialised \code{fmpz} vector. Alternatively,
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\code{NULL} can be passed as the \code{den} variable, in which
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case the denominators will not be stored.
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void fmpq_mat_get_fmpz_mat_rowwise_2(fmpz_mat_t num, fmpz_mat_t num2,
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fmpz * den, const fmpq_mat_t mat, const fmpq_mat_t mat2)
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Clears denominators row by row of both \code{mat} and \code{mat2},
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writing the respective numerators to \code{num} and \code{num2}.
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This is equivalent to concatenating \code{mat} and \code{mat2}
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horizontally, calling \code{fmpq_mat_get_fmpz_mat_rowwise},
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and extracting the two submatrices in the result.
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void fmpq_mat_get_fmpz_mat_colwise(fmpz_mat_t num, fmpz * den,
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const fmpq_mat_t mat)
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Clears denominators in \code{mat} column by column. The rescaled
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numerators are written to \code{num}, and the denominator
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of column \code{i} is written to position \code{i} in \code{den}
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which can be a preinitialised \code{fmpz} vector. Alternatively,
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\code{NULL} can be passed as the \code{den} variable, in which
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case the denominators will not be stored.
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void fmpq_mat_set_fmpz_mat(fmpq_mat_t dest, const fmpz_mat_t src)
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Sets \code{dest} to \code{src}.
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void fmpq_mat_set_fmpz_mat_div_fmpz(fmpq_mat_t mat, const fmpz_mat_t num,
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const fmpz_t den)
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Sets \code{mat} to the integer matrix \code{num} divided by the
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common denominator \code{den}.
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*******************************************************************************
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Modular reduction and rational reconstruction
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*******************************************************************************
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void fmpq_mat_get_fmpz_mat_mod_fmpz(fmpz_mat_t dest, const fmpq_mat_t mat,
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const fmpz_t mod)
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Sets each entry in \code{dest} to the corresponding entry in \code{mat},
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reduced modulo \code{mod}.
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int fmpq_mat_set_fmpz_mat_mod_fmpz(fmpq_mat_t X, const fmpz_mat_t Xmod,
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const fmpz_t mod)
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Set \code{X} to the entrywise rational reconstruction integer matrix
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\code{Xmod} modulo \code{mod}, and returns nonzero if the reconstruction
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is successful. If rational reconstruction fails for any element,
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returns zero and sets the entries in \code{X} to undefined values.
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*******************************************************************************
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Matrix multiplication
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*******************************************************************************
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void fmpq_mat_mul_direct(fmpq_mat_t C, const fmpq_mat_t A, const fmpq_mat_t B)
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Sets \code{C} to the matrix product \code{AB}, computed
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naively using rational arithmetic. This is typically very slow and
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should only be used in circumstances where clearing denominators
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would consume too much memory.
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void fmpq_mat_mul_cleared(fmpq_mat_t C, const fmpq_mat_t A,
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const fmpq_mat_t B)
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Sets \code{C} to the matrix product \code{AB}, computed
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by clearing denominators and multiplying over the integers.
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void fmpq_mat_mul(fmpq_mat_t C, const fmpq_mat_t A, const fmpq_mat_t B)
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Sets \code{C} to the matrix product \code{AB}. This
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simply calls \code{fmpq_mat_mul_cleared}.
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void fmpq_mat_mul_fmpz_mat(fmpq_mat_t C, const fmpq_mat_t A,
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const fmpz_mat_t B)
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Sets \code{C} to the matrix product \code{AB}, with \code{B}
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an integer matrix. This function works efficiently by clearing
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denominators of \code{A}.
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void fmpq_mat_mul_r_fmpz_mat(fmpq_mat_t C, const fmpz_mat_t A,
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const fmpq_mat_t B)
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Sets \code{C} to the matrix product \code{AB}, with \code{A}
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an integer matrix. This function works efficiently by clearing
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denominators of \code{B}.
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*******************************************************************************
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Trace
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*******************************************************************************
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void fmpq_mat_trace(fmpq_t trace, const fmpq_mat_t mat)
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Computes the trace of the matrix, i.e. the sum of the entries on
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the main diagonal. The matrix is required to be square.
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*******************************************************************************
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Determinant
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*******************************************************************************
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void fmpq_mat_det(fmpq_t det, const fmpq_mat_t mat)
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Sets \code{det} to the determinant of \code{mat}. In the general case,
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the determinant is computed by clearing denominators and computing a
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determinant over the integers. Matrices of size 0, 1 or 2 are handled
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directly.
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*******************************************************************************
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Nonsingular solving
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*******************************************************************************
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int fmpq_mat_solve_fraction_free(fmpq_mat_t X, const fmpq_mat_t A,
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const fmpq_mat_t B)
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Solves \code{AX = B} for nonsingular \code{A} by clearing denominators
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and solving the rescaled system over the integers using a fraction-free
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algorithm. This is usually the fastest algorithm for small systems.
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Returns nonzero if \code{X} is nonsingular or if the right hand side
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is empty, and zero otherwise.
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int fmpq_mat_solve_dixon(fmpq_mat_t X, const fmpq_mat_t A, const fmpq_mat_t B)
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Solves \code{AX = B} for nonsingular \code{A} by clearing denominators
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and solving the rescaled system over the integers using Dixon's algorithm.
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The rational solution matrix is generated using rational reconstruction.
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This is usually the fastest algorithm for large systems.
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Returns nonzero if \code{X} is nonsingular or if the right hand side
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is empty, and zero otherwise.
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*******************************************************************************
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Inverse
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*******************************************************************************
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int fmpq_mat_inv(fmpq_mat_t B, const fmpq_mat_t A)
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Sets \code{B} to the inverse matrix of \code{A} and returns nonzero.
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Returns zero if \code{A} is singular. \code{A} must be a square matrix.
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*******************************************************************************
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Echelon form
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*******************************************************************************
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int fmpq_mat_pivot(slong * perm, fmpq_mat_t mat, slong r, slong c)
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Helper function for row reduction. Returns 1 if the entry of \code{mat}
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at row $r$ and column $c$ is nonzero. Otherwise searches for a nonzero
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entry in the same column among rows $r+1, r+2, \ldots$. If a nonzero
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entry is found at row $s$, swaps rows $r$ and $s$ and the corresponding
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entries in \code{perm} (unless \code{NULL}) and returns -1. If no
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nonzero pivot entry is found, leaves the inputs unchanged and returns 0.
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slong fmpq_mat_rref_classical(fmpq_mat_t B, const fmpq_mat_t A)
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Sets \code{B} to the reduced row echelon form of \code{A} and returns
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the rank. Performs Gauss-Jordan elimination directly over the rational
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numbers. This algorithm is usually inefficient and is mainly intended
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to be used for testing purposes.
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slong fmpq_mat_rref_fraction_free(fmpq_mat_t B, const fmpq_mat_t A)
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Sets \code{B} to the reduced row echelon form of \code{A} and returns
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the rank. Clears denominators and performs fraction-free Gauss-Jordan
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elimination using \code{fmpz_mat} functions.
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slong fmpq_mat_rref(fmpq_mat_t B, const fmpq_mat_t A)
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Sets \code{B} to the reduced row echelon form of \code{A} and returns
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the rank. This function automatically chooses between the classical and
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fraction-free algorithms depending on the size of the matrix.
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