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1 /* ----------------------------------------------------------------------
2  * Project:      CMSIS DSP Library
3  * Title:        arm_mat_cholesky_f16.c
4  * Description:  Floating-point Cholesky decomposition
5  *
6  * $Date:        23 April 2021
7  * $Revision:    V1.9.0
8  *
9  * Target Processor: Cortex-M and Cortex-A cores
10  * -------------------------------------------------------------------- */
11 /*
12  * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
13  *
14  * SPDX-License-Identifier: Apache-2.0
15  *
16  * Licensed under the Apache License, Version 2.0 (the License); you may
17  * not use this file except in compliance with the License.
18  * You may obtain a copy of the License at
19  *
20  * www.apache.org/licenses/LICENSE-2.0
21  *
22  * Unless required by applicable law or agreed to in writing, software
23  * distributed under the License is distributed on an AS IS BASIS, WITHOUT
24  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
25  * See the License for the specific language governing permissions and
26  * limitations under the License.
27  */
28 
29 #include "dsp/matrix_functions_f16.h"
30 #include "dsp/matrix_utils.h"
31 
32 #if defined(ARM_FLOAT16_SUPPORTED)
33 
34 /**
35   @ingroup groupMatrix
36  */
37 
38 /**
39   @addtogroup MatrixChol
40   @{
41  */
42 
43 /**
44    * @brief Floating-point Cholesky decomposition of positive-definite matrix.
45    * @param[in]  pSrc   points to the instance of the input floating-point matrix structure.
46    * @param[out] pDst   points to the instance of the output floating-point matrix structure.
47    * @return The function returns ARM_MATH_SIZE_MISMATCH, if the dimensions do not match.
48    * @return        execution status
49                    - \ref ARM_MATH_SUCCESS       : Operation successful
50                    - \ref ARM_MATH_SIZE_MISMATCH : Matrix size check failed
51                    - \ref ARM_MATH_DECOMPOSITION_FAILURE      : Input matrix cannot be decomposed
52    * @par
53    * If the matrix is ill conditioned or only semi-definite, then it is better using the LDL^t decomposition.
54    * The decomposition of A is returning a lower triangular matrix U such that A = L L^t
55    */
56 
57 #if defined(ARM_MATH_MVE_FLOAT16) && !defined(ARM_MATH_AUTOVECTORIZE)
58 
59 #include "arm_helium_utils.h"
60 
arm_mat_cholesky_f16(const arm_matrix_instance_f16 * pSrc,arm_matrix_instance_f16 * pDst)61 arm_status arm_mat_cholesky_f16(
62   const arm_matrix_instance_f16 * pSrc,
63         arm_matrix_instance_f16 * pDst)
64 {
65 
66   arm_status status;                             /* status of matrix inverse */
67 
68 
69 #ifdef ARM_MATH_MATRIX_CHECK
70 
71   /* Check for matrix mismatch condition */
72   if ((pSrc->numRows != pSrc->numCols) ||
73       (pDst->numRows != pDst->numCols) ||
74       (pSrc->numRows != pDst->numRows)   )
75   {
76     /* Set status as ARM_MATH_SIZE_MISMATCH */
77     status = ARM_MATH_SIZE_MISMATCH;
78   }
79   else
80 
81 #endif /* #ifdef ARM_MATH_MATRIX_CHECK */
82 
83   {
84     int i,j,k;
85     int n = pSrc->numRows;
86     _Float16 invSqrtVj;
87     float16_t *pA,*pG;
88     int kCnt;
89 
90     mve_pred16_t p0;
91 
92     f16x8_t acc, acc0, acc1, acc2, acc3;
93     f16x8_t vecGi;
94     f16x8_t vecGj,vecGj0,vecGj1,vecGj2,vecGj3;
95 
96 
97     pA = pSrc->pData;
98     pG = pDst->pData;
99 
100     for(i=0 ;i < n ; i++)
101     {
102        for(j=i ; j+3 < n ; j+=4)
103        {
104           acc0 = vdupq_n_f16(0.0f16);
105           acc0[0]=pA[(j + 0) * n + i];
106 
107           acc1 = vdupq_n_f16(0.0f16);
108           acc1[0]=pA[(j + 1) * n + i];
109 
110           acc2 = vdupq_n_f16(0.0f16);
111           acc2[0]=pA[(j + 2) * n + i];
112 
113           acc3 = vdupq_n_f16(0.0f16);
114           acc3[0]=pA[(j + 3) * n + i];
115 
116           kCnt = i;
117           for(k=0; k < i ; k+=8)
118           {
119              p0 = vctp16q(kCnt);
120 
121              vecGi=vldrhq_z_f16(&pG[i * n + k],p0);
122 
123              vecGj0=vldrhq_z_f16(&pG[(j + 0) * n + k],p0);
124              vecGj1=vldrhq_z_f16(&pG[(j + 1) * n + k],p0);
125              vecGj2=vldrhq_z_f16(&pG[(j + 2) * n + k],p0);
126              vecGj3=vldrhq_z_f16(&pG[(j + 3) * n + k],p0);
127 
128              acc0 = vfmsq_m(acc0, vecGi, vecGj0, p0);
129              acc1 = vfmsq_m(acc1, vecGi, vecGj1, p0);
130              acc2 = vfmsq_m(acc2, vecGi, vecGj2, p0);
131              acc3 = vfmsq_m(acc3, vecGi, vecGj3, p0);
132 
133              kCnt -= 8;
134           }
135           pG[(j + 0) * n + i] = vecAddAcrossF16Mve(acc0);
136           pG[(j + 1) * n + i] = vecAddAcrossF16Mve(acc1);
137           pG[(j + 2) * n + i] = vecAddAcrossF16Mve(acc2);
138           pG[(j + 3) * n + i] = vecAddAcrossF16Mve(acc3);
139        }
140 
141        for(; j < n ; j++)
142        {
143 
144           kCnt = i;
145           acc = vdupq_n_f16(0.0f16);
146           acc[0] = pA[j * n + i];
147 
148           for(k=0; k < i ; k+=8)
149           {
150              p0 = vctp16q(kCnt);
151 
152              vecGi=vldrhq_z_f16(&pG[i * n + k],p0);
153              vecGj=vldrhq_z_f16(&pG[j * n + k],p0);
154 
155              acc = vfmsq_m(acc, vecGi, vecGj,p0);
156 
157              kCnt -= 8;
158           }
159           pG[j * n + i] = vecAddAcrossF16Mve(acc);
160        }
161 
162        if ((_Float16)pG[i * n + i] <= 0.0f16)
163        {
164          return(ARM_MATH_DECOMPOSITION_FAILURE);
165        }
166 
167        invSqrtVj = 1.0f16/(_Float16)sqrtf((float32_t)pG[i * n + i]);
168        SCALE_COL_F16(pDst,i,invSqrtVj,i);
169     }
170 
171     status = ARM_MATH_SUCCESS;
172 
173   }
174 
175 
176   /* Return to application */
177   return (status);
178 }
179 
180 #else
arm_mat_cholesky_f16(const arm_matrix_instance_f16 * pSrc,arm_matrix_instance_f16 * pDst)181 arm_status arm_mat_cholesky_f16(
182   const arm_matrix_instance_f16 * pSrc,
183         arm_matrix_instance_f16 * pDst)
184 {
185 
186   arm_status status;                             /* status of matrix inverse */
187 
188 
189 #ifdef ARM_MATH_MATRIX_CHECK
190 
191   /* Check for matrix mismatch condition */
192   if ((pSrc->numRows != pSrc->numCols) ||
193       (pDst->numRows != pDst->numCols) ||
194       (pSrc->numRows != pDst->numRows)   )
195   {
196     /* Set status as ARM_MATH_SIZE_MISMATCH */
197     status = ARM_MATH_SIZE_MISMATCH;
198   }
199   else
200 
201 #endif /* #ifdef ARM_MATH_MATRIX_CHECK */
202 
203   {
204     int i,j,k;
205     int n = pSrc->numRows;
206     float16_t invSqrtVj;
207     float16_t *pA,*pG;
208 
209     pA = pSrc->pData;
210     pG = pDst->pData;
211 
212 
213     for(i=0 ; i < n ; i++)
214     {
215        for(j=i ; j < n ; j++)
216        {
217           pG[j * n + i] = pA[j * n + i];
218 
219           for(k=0; k < i ; k++)
220           {
221              pG[j * n + i] = (_Float16)pG[j * n + i] - (_Float16)pG[i * n + k] * (_Float16)pG[j * n + k];
222           }
223        }
224 
225        if ((_Float16)pG[i * n + i] <= 0.0f16)
226        {
227          return(ARM_MATH_DECOMPOSITION_FAILURE);
228        }
229 
230        /* The division is done in float32 for accuracy reason and
231        because doing it in f16 would not have any impact on the performances.
232        */
233        invSqrtVj = 1.0f/sqrtf((float32_t)pG[i * n + i]);
234        SCALE_COL_F16(pDst,i,invSqrtVj,i);
235 
236     }
237 
238     status = ARM_MATH_SUCCESS;
239 
240   }
241 
242 
243   /* Return to application */
244   return (status);
245 }
246 
247 #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
248 
249 /**
250   @} end of MatrixChol group
251  */
252 #endif /* #if defined(ARM_FLOAT16_SUPPORTED) */
253