1 // SPDX-License-Identifier: Apache-2.0 2 // 3 // Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au) 4 // Copyright 2008-2016 National ICT Australia (NICTA) 5 // 6 // Licensed under the Apache License, Version 2.0 (the "License"); 7 // you may not use this file except in compliance with the License. 8 // You may obtain a copy of the License at 9 // http://www.apache.org/licenses/LICENSE-2.0 10 // 11 // Unless required by applicable law or agreed to in writing, software 12 // distributed under the License is distributed on an "AS IS" BASIS, 13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 // See the License for the specific language governing permissions and 15 // limitations under the License. 16 // ------------------------------------------------------------------------ 17 18 19 //! \addtogroup trimat_helper 20 //! @{ 21 22 23 namespace trimat_helper 24 { 25 26 27 28 template<typename eT> 29 inline 30 bool is_triu(const Mat<eT> & A)31is_triu(const Mat<eT>& A) 32 { 33 arma_extra_debug_sigprint(); 34 35 // NOTE: assuming that A has a square size 36 37 const uword N = A.n_rows; 38 const uword Nm1 = N-1; 39 40 if(N < 2) { return false; } 41 42 const eT* A_mem = A.memptr(); 43 const eT eT_zero = eT(0); 44 45 // quickly check bottom-left corner 46 const eT* A_col0 = A_mem; 47 const eT* A_col1 = A_col0 + N; 48 49 if( (A_col0[N-2] != eT_zero) || (A_col0[Nm1] != eT_zero) || (A_col1[Nm1] != eT_zero) ) { return false; } 50 51 // if we got to this point, do a thorough check 52 53 const eT* A_col = A_mem; 54 55 for(uword j=0; j < Nm1; ++j) 56 { 57 for(uword i=(j+1); i < N; ++i) 58 { 59 const eT A_ij = A_col[i]; 60 61 if(A_ij != eT_zero) { return false; } 62 } 63 64 A_col += N; 65 } 66 67 return true; 68 } 69 70 71 72 template<typename eT> 73 inline 74 bool is_tril(const Mat<eT> & A)75is_tril(const Mat<eT>& A) 76 { 77 arma_extra_debug_sigprint(); 78 79 // NOTE: assuming that A has a square size 80 81 const uword N = A.n_rows; 82 83 if(N < 2) { return false; } 84 85 const eT eT_zero = eT(0); 86 87 // quickly check top-right corner 88 const eT* A_colNm2 = A.colptr(N-2); 89 const eT* A_colNm1 = A_colNm2 + N; 90 91 if( (A_colNm2[0] != eT_zero) || (A_colNm1[0] != eT_zero) || (A_colNm1[1] != eT_zero) ) { return false; } 92 93 // if we got to this point, do a thorough check 94 95 const eT* A_col = A.memptr() + N; 96 97 for(uword j=1; j < N; ++j) 98 { 99 for(uword i=0; i < j; ++i) 100 { 101 const eT A_ij = A_col[i]; 102 103 if(A_ij != eT_zero) { return false; } 104 } 105 106 A_col += N; 107 } 108 109 return true; 110 } 111 112 113 114 } // end of namespace trimat_helper 115 116 117 //! @} 118