package owl
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doc/owl/Owl_sparse_matrix_generic/index.html
Module Owl_sparse_matrix_generic
Sparse matrix module
Type definition
type ('a, 'b) kind = ('a, 'b) Bigarray.kind
Type of sparse matrices. It is defined in ``types.ml`` as record type.
Create sparse matrices
``zeros m n`` creates an ``m`` by ``n`` matrix where all the elements are zeros. This operation is very fast since it only allocates a small amount of memory. The memory will grow automatically as more elements are inserted.
``ones m n`` creates an ``m`` by ``n`` matrix where all the elements are ones. This operation can be very slow if matrix size is big. You might consider to use dense matrix for better performance in this case.
``binary m n`` creates an ``m`` by ``n`` random matrix where 10% ~ 15% elements are 1.
``uniform m n`` creates an ``m`` by ``n`` matrix where 10% ~ 15% elements follow a uniform distribution in ``(0,1)`` interval. ``uniform ~scale:a m n`` adjusts the interval to ``(0,a)``.
Obtain the basic properties
val shape : ('a, 'b) t -> int * int
If ``x`` is an ``m`` by ``n`` matrix, ``shape x`` returns ``(m,n)``, i.e., the size of two dimensions of ``x``.
val row_num : ('a, 'b) t -> int
``row_num x`` returns the number of rows in matrix ``x``.
val col_num : ('a, 'b) t -> int
``col_num x`` returns the number of columns in matrix ``x``.
val row_num_nz : ('a, 'b) t -> int
``row_num_nz x`` returns the number of non-zero rows in matrix ``x``.
val col_num_nz : ('a, 'b) t -> int
``col_num_nz x`` returns the number of non-zero columns in matrix ``x``.
val numel : ('a, 'b) t -> int
``numel x`` returns the number of elements in matrix ``x``. It is equivalent to ``(row_num x) * (col_num x)``.
val nnz : ('a, 'b) t -> int
``nnz x`` returns the number of non-zero elements in matrix ``x``.
val nnz_rows : ('a, 'b) t -> int array
``nnz_rows x`` returns the number of non-zero rows in matrix ``x``. A non-zero row means there is at least one non-zero element in that row.
val nnz_cols : ('a, 'b) t -> int array
``nnz_cols x`` returns the number of non-zero cols in matrix ``x``.
val density : ('a, 'b) t -> float
``density x`` returns the density of non-zero element. This operation is equivalent to ``nnz x`` divided by ``numel x``.
Manipulate a matrix
val get : ('a, 'b) t -> int -> int -> 'a
``set x i j a`` sets the element ``(i,j)`` of ``x`` to value ``a``.
val set : ('a, 'b) t -> int -> int -> 'a -> unit
``get x i j`` returns the value of element ``(i,j)`` of ``x``.
val insert : ('a, 'b) t -> int -> int -> 'a -> unit
val reset : ('a, 'b) t -> unit
``reset x`` resets all the elements in ``x`` to ``0``.
val fill : ('a, 'b) t -> 'a -> unit
TODO
``copy x`` makes an exact copy of matrix ``x``. Note that the copy becomes mutable no matter ``w`` is mutable or not. This is especially useful if you want to modify certain elements in an immutable matrix from math operations.
``transpose x`` transposes an ``m`` by ``n`` matrix to ``n`` by ``m`` one.
``rows x a`` returns the rows (defined in an int array ``a``) of ``x``. The returned rows will be combined into a new sparse matrix. The order of rows in the new matrix is the same as that in the array ``a``.
Similar to ``rows``, ``cols x a`` returns the columns (specified in array ``a``) of x in a new sparse matrix.
val prune : ('a, 'b) t -> 'a -> float -> unit
``prune x ...``
``concat_vertical x y`` not implemented yet
``concat_horizontal x y`` not implemented yet
Iterate elements, columns, and rows
val iteri : (int -> int -> 'a -> unit) -> ('a, 'b) t -> unit
``iteri f x`` iterates all the elements in ``x`` and applies the user defined function ``f : int -> int -> float -> 'a``. ``f i j v`` takes three parameters, ``i`` and ``j`` are the coordinates of current element, and ``v`` is its value.
val iter : ('a -> unit) -> ('a, 'b) t -> unit
``iter f x`` is the same as as ``iteri f x`` except the coordinates of the current element is not passed to the function ``f : float -> 'a``
``mapi f x`` maps each element in ``x`` to a new value by applying ``f : int -> int -> float -> float``. The first two parameters are the coordinates of the element, and the third parameter is the value.
``map f x`` is similar to ``mapi f x`` except the coordinates of the current element is not passed to the function ``f : float -> float``
val foldi : (int -> int -> 'c -> 'a -> 'c) -> 'c -> ('a, 'b) t -> 'c
val fold : ('c -> 'a -> 'c) -> 'c -> ('a, 'b) t -> 'c
``fold f a x`` folds all the elements in ``x`` with the function ``f : 'a -> float -> 'a``. For an ``m`` by ``n`` matrix ``x``, the order of folding is from ``(0,0)`` to ``(m-1,n-1)``, row by row.
val filteri : (int -> int -> 'a -> bool) -> ('a, 'b) t -> (int * int) array
``filteri f x`` uses ``f : int -> int -> float -> bool`` to filter out certain elements in ``x``. An element will be included if ``f`` returns ``true``. The returned result is a list of coordinates of the selected elements.
val filter : ('a -> bool) -> ('a, 'b) t -> (int * int) array
Similar to ``filteri``, but the coordinates of the elements are not passed to the function ``f : float -> bool``.
``iteri_rows f x`` iterates every row in ``x`` and applies function ``f : int -> mat -> unit`` to each of them.
Similar to ``iteri_rows`` except row number is not passed to ``f``.
``iteri_cols f x`` iterates every column in ``x`` and applies function ``f : int -> mat -> unit`` to each of them. Column number is passed to ``f`` as the first parameter.
Similar to ``iteri_cols`` except col number is not passed to ``f``.
``mapi_rows f x`` maps every row in ``x`` to a type ``'a`` value by applying function ``f : int -> mat -> 'a`` to each of them. The results is an array of all the returned values.
Similar to ``mapi_rows`` except row number is not passed to ``f``.
``mapi_cols f x`` maps every column in ``x`` to a type ``'a`` value by applying function ``f : int -> mat -> 'a``.
Similar to ``mapi_cols`` except column number is not passed to ``f``.
``fold_rows f a x`` folds all the rows in ``x`` using function ``f``. The order of folding is from the first row to the last one.
``fold_cols f a x`` folds all the columns in ``x`` using function ``f``. The order of folding is from the first column to the last one.
val iteri_nz : (int -> int -> 'a -> unit) -> ('a, 'b) t -> unit
``iteri_nz f x`` iterates all the non-zero elements in ``x`` by applying the function ``f : int -> int -> float -> 'a``. It is much faster than ``iteri``.
val iter_nz : ('a -> unit) -> ('a, 'b) t -> unit
Similar to ``iter_nz`` except the coordinates of elements are not passed to ``f``.
``mapi_nz f x`` is similar to ``mapi f x`` but only applies ``f`` to non-zero elements in ``x``. The zeros in ``x`` will remain the same in the new matrix.
Similar to ``mapi_nz`` except the coordinates of elements are not passed to ``f``.
val foldi_nz : (int -> int -> 'c -> 'a -> 'c) -> 'c -> ('a, 'b) t -> 'c
TODO
val fold_nz : ('c -> 'a -> 'c) -> 'c -> ('a, 'b) t -> 'c
``fold_nz f a x`` is similar to ``fold f a x`` but only applies to non-zero rows in ``x``. zero rows will be simply skipped in folding.
val filteri_nz : (int -> int -> 'a -> bool) -> ('a, 'b) t -> (int * int) array
``filteri_nz f x`` is similar to ``filter f x`` but only applies ``f`` to non-zero elements in ``x``.
val filter_nz : ('a -> bool) -> ('a, 'b) t -> (int * int) array
``filter_nz f x`` is similar to ``filteri_nz`` except that the coordinates of matrix elements are not passed to ``f``.
``iteri_rows_nz f x`` is similar to ``iteri_rows`` but only applies ``f`` to non-zero rows in ``x``.
Similar to ``iteri_rows_nz`` except that row numbers are not passed to ``f``.
``iteri_cols_nz f x`` is similar to ``iteri_cols`` but only applies ``f`` to non-zero columns in ``x``.
Similar to ``iteri_cols_nz`` except that column numbers are not passed to ``f``.
``mapi_rows_nz f x`` applies ``f`` only to the non-zero rows in ``x``.
Similar to ``mapi_rows_nz``, but row numbers are not passed to ``f``.
``mapi_cols_nz f x`` applies ``f`` only to the non-zero columns in ``x``.
Similar to ``mapi_cols_nz``, but columns numbers are not passed to ``f``.
``fold_rows_nz f a x`` is similar to ``fold_rows`` but only folds non-zero rows in ``x`` using function ``f``. Zero rows will be dropped in iterating ``x``.
``fold_cols_nz f a x`` is similar to ``fold_cols`` but only folds non-zero columns in ``x`` using function ``f``. Zero columns will be dropped in iterating ``x``.
Examine elements and compare two matrices
val exists : ('a -> bool) -> ('a, 'b) t -> bool
``exists f x`` checks all the elements in ``x`` using ``f``. If at least one element satisfies ``f`` then the function returns ``true`` otherwise ``false``.
val not_exists : ('a -> bool) -> ('a, 'b) t -> bool
``not_exists f x`` checks all the elements in ``x``, the function returns ``true`` only if all the elements fail to satisfy ``f : float -> bool``.
val for_all : ('a -> bool) -> ('a, 'b) t -> bool
``for_all f x`` checks all the elements in ``x``, the function returns ``true`` if and only if all the elements pass the check of function ``f``.
val exists_nz : ('a -> bool) -> ('a, 'b) t -> bool
``exists_nz f x`` is similar to ``exists`` but only checks non-zero elements.
val not_exists_nz : ('a -> bool) -> ('a, 'b) t -> bool
``not_exists_nz f x`` is similar to ``not_exists`` but only checks non-zero elements.
val for_all_nz : ('a -> bool) -> ('a, 'b) t -> bool
``for_all_nz f x`` is similar to ``for_all_nz`` but only checks non-zero elements.
val is_zero : ('a, 'b) t -> bool
``is_zero x`` returns ``true`` if all the elements in ``x`` are zeros.
val is_positive : ('a, 'b) t -> bool
``is_positive x`` returns ``true`` if all the elements in ``x`` are positive.
val is_negative : ('a, 'b) t -> bool
``is_negative x`` returns ``true`` if all the elements in ``x`` are negative.
val is_nonpositive : ('a, 'b) t -> bool
``is_nonpositive`` returns ``true`` if all the elements in ``x`` are non-positive.
val is_nonnegative : ('a, 'b) t -> bool
``is_nonnegative`` returns ``true`` if all the elements in ``x`` are non-negative.
``equal x y`` returns ``true`` if two matrices ``x`` and ``y`` are equal.
``not_equal x y`` returns ``true`` if there is at least one element in ``x`` is not equal to that in ``y``.
``greater x y`` returns ``true`` if all the elements in ``x`` are greater than the corresponding elements in ``y``.
``less x y`` returns ``true`` if all the elements in ``x`` are smaller than the corresponding elements in ``y``.
``greater_equal x y`` returns ``true`` if all the elements in ``x`` are not smaller than the corresponding elements in ``y``.
``less_equal x y`` returns ``true`` if all the elements in ``x`` are not greater than the corresponding elements in ``y``.
Randomisation functions
``permutation_matrix m`` returns an ``m`` by ``m`` permutation matrix.
``draw_rows x m`` draws ``m`` rows randomly from ``x``. The row indices are also returned in an int array along with the selected rows. The parameter ``replacement`` indicates whether the drawing is by replacement or not.
``draw_cols x m`` draws ``m`` cols randomly from ``x``. The column indices are also returned in an int array along with the selected columns. The parameter ``replacement`` indicates whether the drawing is by replacement or not.
``shuffle_rows x`` shuffles all the rows in matrix ``x``.
``shuffle_cols x`` shuffles all the columns in matrix ``x``.
``shuffle x`` shuffles all the elements in ``x`` by first shuffling along the rows then shuffling along columns. It is equivalent to ``shuffle_cols (shuffle_rows x)``.
Input/Output and helper functions
val to_array : ('a, 'b) t -> (int array * 'a) array
TODO
val to_dense : ('a, 'b) t -> ('a, 'b) Owl_dense_matrix_generic.t
``to_dense x`` converts ``x`` into a dense matrix.
val of_dense : ('a, 'b) Owl_dense_matrix_generic.t -> ('a, 'b) t
``of_dense x`` returns a sparse matrix from the dense matrix ``x``.
val print : ('a, 'b) t -> unit
``print x`` pretty prints matrix ``x`` without headings.
val pp_spmat : ('a, 'b) t -> unit
``pp_spmat x`` pretty prints matrix ``x`` with headings. Toplevel uses this function to print out the matrices.
val save : ('a, 'b) t -> string -> unit
``save x f`` saves the matrix ``x`` to a file with the name ``f``. The format is binary by using ``Marshal`` module to serialise the matrix.
``load k f`` loads a sparse matrix from file ``f``. The file must be previously saved by using ``save`` function.
Unary mathematical operations
val min : (float, 'a) t -> float
``min x`` returns the minimum value of all elements in ``x``.
val max : (float, 'a) t -> float
``max x`` returns the maximum value of all elements in ``x``.
val minmax : (float, 'a) t -> float * float
``minmax x`` returns both the minimum and minimum values in ``x``.
val trace : ('a, 'b) t -> 'a
``trace x`` returns the sum of diagonal elements in ``x``.
val sum : ('a, 'b) t -> 'a
``sum x`` returns the summation of all the elements in ``x``.
val mean : ('a, 'b) t -> 'a
``mean x`` returns the mean value of all the elements in ``x``. It is equivalent to calculate ``sum x`` divided by ``numel x``
``sum_rows x`` returns the summation of all the row vectors in ``x``.
``sum_cols`` returns the summation of all the column vectors in ``x``.
``mean_rows x`` returns the mean value of all row vectors in ``x``. It is equivalent to ``div_scalar (sum_rows x) (float_of_int (row_num x))``.
``mean_cols x`` returns the mean value of all column vectors in ``x``. It is equivalent to ``div_scalar (sum_cols x) (float_of_int (col_num x))``.
``abs x`` returns a new matrix where each element has the absolute value of that in the original matrix ``x``.
``neg x`` returns a new matrix where each element has the negative value of that in the original matrix ``x``.
val l1norm : (float, 'b) t -> float
TODO
val l2norm : (float, 'b) t -> float
TODO
Binary mathematical operations
``add x y`` adds two matrices ``x`` and ``y``. Both must have the same dimensions.
``sub x y`` subtracts the matrix ``x`` from ``y``. Both must have the same dimensions.
``mul x y`` performs an element-wise multiplication, so both ``x`` and ``y`` must have the same dimensions.
``div x y`` performs an element-wise division, so both ``x`` and ``y`` must have the same dimensions.
``dot x y`` calculates the dot product of an ``m`` by ``n`` matrix ``x`` and another ``n`` by ``p`` matrix ``y``.
``mul_scalar x a`` multiplies every element in ``x`` by a constant factor ``a``.
``div_scalar x a`` divides every element in ``x`` by a constant factor ``a``.
``power x a`` calculates the power of ``a`` of each element in ``x``.
ends here