######################################################## Copyright (c) 2015, ArrayFire# All rights reserved.## This file is distributed under 3-clause BSD license.# The complete license agreement can be obtained at:# http://arrayfire.com/licenses/BSD-3-Clause########################################################"""Functions to create and manipulate sparse matrices."""from.libraryimport*from.arrayimport*importnumbersfrom.interopimportto_array__to_sparse_enum=[STORAGE.DENSE,STORAGE.CSR,STORAGE.CSC,STORAGE.COO][docs]defcreate_sparse(values,row_idx,col_idx,nrows,ncols,storage=STORAGE.CSR):""" Create a sparse matrix from it's constituent parts. Parameters ---------- values : af.Array. - Contains the non zero elements of the sparse array. row_idx : af.Array. - Contains row indices of the sparse array. col_idx : af.Array. - Contains column indices of the sparse array. nrows : int. - specifies the number of rows in sparse matrix. ncols : int. - specifies the number of columns in sparse matrix. storage : optional: arrayfire.STORAGE. default: arrayfire.STORAGE.CSR. - Can be one of arrayfire.STORAGE.CSR, arrayfire.STORAGE.COO. Returns ------- A sparse matrix. """assert(isinstance(values,Array))assert(isinstance(row_idx,Array))assert(isinstance(col_idx,Array))out=Array()safe_call(backend.get().af_create_sparse_array(c_pointer(out.arr),c_dim_t(nrows),c_dim_t(ncols),values.arr,row_idx.arr,col_idx.arr,storage.value))returnout [docs]defcreate_sparse_from_host(values,row_idx,col_idx,nrows,ncols,storage=STORAGE.CSR):""" Create a sparse matrix from it's constituent parts. Parameters ---------- values : Any datatype that can be converted to array. - Contains the non zero elements of the sparse array. row_idx : Any datatype that can be converted to array. - Contains row indices of the sparse array. col_idx : Any datatype that can be converted to array. - Contains column indices of the sparse array. nrows : int. - specifies the number of rows in sparse matrix. ncols : int. - specifies the number of columns in sparse matrix. storage : optional: arrayfire.STORAGE. default: arrayfire.STORAGE.CSR. - Can be one of arrayfire.STORAGE.CSR, arrayfire.STORAGE.COO. Returns ------- A sparse matrix. """returncreate_sparse(to_array(values),to_array(row_idx).as_type(Dtype.s32),to_array(col_idx).as_type(Dtype.s32),nrows,ncols,storage) [docs]defcreate_sparse_from_dense(dense,storage=STORAGE.CSR):""" Create a sparse matrix from a dense matrix. Parameters ---------- dense : af.Array. - A dense matrix. storage : optional: arrayfire.STORAGE. default: arrayfire.STORAGE.CSR. - Can be one of arrayfire.STORAGE.CSR, arrayfire.STORAGE.COO. Returns ------- A sparse matrix. """assert(isinstance(dense,Array))out=Array()safe_call(backend.get().af_create_sparse_array_from_dense(c_pointer(out.arr),dense.arr,storage.value))returnout [docs]defconvert_sparse_to_dense(sparse):""" Create a dense matrix from a sparse matrix. Parameters ---------- sparse : af.Array. - A sparse matrix. Returns ------- A dense matrix. """out=Array()safe_call(backend.get().af_sparse_to_dense(c_pointer(out.arr),sparse.arr))returnout [docs]defsparse_get_info(sparse):""" Get the constituent arrays and storage info from a sparse matrix. Parameters ---------- sparse : af.Array. - A sparse matrix. Returns -------- (values, row_idx, col_idx, storage) where values : arrayfire.Array containing non zero elements from sparse matrix row_idx : arrayfire.Array containing the row indices col_idx : arrayfire.Array containing the column indices storage : sparse storage """values=Array()row_idx=Array()col_idx=Array()stype=c_int_t(0)safe_call(backend.get().af_sparse_get_info(c_pointer(values.arr),c_pointer(row_idx.arr),c_pointer(col_idx.arr),c_pointer(stype),sparse.arr))return(values,row_idx,col_idx,__to_sparse_enum[stype.value]) [docs]defsparse_get_values(sparse):""" Get the non zero values from sparse matrix. Parameters ---------- sparse : af.Array. - A sparse matrix. Returns -------- arrayfire array containing the non zero elements. """values=Array()safe_call(backend.get().af_sparse_get_values(c_pointer(values.arr),sparse.arr))returnvalues [docs]defsparse_get_row_idx(sparse):""" Get the row indices from sparse matrix. Parameters ---------- sparse : af.Array. - A sparse matrix. Returns -------- arrayfire array containing the non zero elements. """row_idx=Array()safe_call(backend.get().af_sparse_get_row_idx(c_pointer(row_idx.arr),sparse.arr))returnrow_idx [docs]defsparse_get_col_idx(sparse):""" Get the column indices from sparse matrix. Parameters ---------- sparse : af.Array. - A sparse matrix. Returns -------- arrayfire array containing the non zero elements. """col_idx=Array()safe_call(backend.get().af_sparse_get_col_idx(c_pointer(col_idx.arr),sparse.arr))returncol_idx [docs]defsparse_get_nnz(sparse):""" Get the column indices from sparse matrix. Parameters ---------- sparse : af.Array. - A sparse matrix. Returns -------- Number of non zero elements in the sparse matrix. """nnz=c_dim_t(0)safe_call(backend.get().af_sparse_get_nnz(c_pointer(nnz),sparse.arr))returnnnz.value [docs]defsparse_get_storage(sparse):""" Get the column indices from sparse matrix. Parameters ---------- sparse : af.Array. - A sparse matrix. Returns -------- Number of non zero elements in the sparse matrix. """storage=c_int_t(0)safe_call(backend.get().af_sparse_get_storage(c_pointer(storage),sparse.arr))return__to_sparse_enum[storage.value] [docs]defconvert_sparse(sparse,storage):""" Convert sparse matrix from one format to another. Parameters ---------- storage : arrayfire.STORAGE. Returns ------- Sparse matrix converted to the appropriate type. """out=Array()safe_call(backend.get().af_sparse_convert_to(c_pointer(out.arr),sparse.arr,storage.value))returnout
