|
| 1 | +<!-- |
| 2 | +
|
| 3 | +@license Apache-2.0 |
| 4 | +
|
| 5 | +Copyright (c) 2025 The Stdlib Authors. |
| 6 | +
|
| 7 | +Licensed under the Apache License, Version 2.0 (the "License"); |
| 8 | +you may not use this file except in compliance with the License. |
| 9 | +You may obtain a copy of the License at |
| 10 | +
|
| 11 | + http://www.apache.org/licenses/LICENSE-2.0 |
| 12 | +
|
| 13 | +Unless required by applicable law or agreed to in writing, software |
| 14 | +distributed under the License is distributed on an "AS IS" BASIS, |
| 15 | +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 16 | +See the License for the specific language governing permissions and |
| 17 | +limitations under the License. |
| 18 | +
|
| 19 | +--> |
| 20 | + |
| 21 | +# sger |
| 22 | + |
| 23 | +> Perform the rank 1 operation `A = α*x*y^T + A`. |
| 24 | +
|
| 25 | +<section class="intro"> |
| 26 | + |
| 27 | +</section> |
| 28 | + |
| 29 | +<!-- /.intro --> |
| 30 | + |
| 31 | +<section class="usage"> |
| 32 | + |
| 33 | +## Usage |
| 34 | + |
| 35 | +```javascript |
| 36 | +var sger = require( '@stdlib/blas/base/sger' ); |
| 37 | +``` |
| 38 | + |
| 39 | +#### sger( order, M, N, α, x, sx, y, sy, A, lda ) |
| 40 | + |
| 41 | +Performs the rank 1 operation `A = α*x*y^T + A`, where `α` is a scalar, `x` is an `M` element vector, `y` is an `N` element vector, and `A` is an `M` by `N` matrix. |
| 42 | + |
| 43 | +```javascript |
| 44 | +var Float32Array = require( '@stdlib/array/float32' ); |
| 45 | + |
| 46 | +var A = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] ); |
| 47 | +var x = new Float32Array( [ 1.0, 1.0 ] ); |
| 48 | +var y = new Float32Array( [ 1.0, 1.0, 1.0 ] ); |
| 49 | + |
| 50 | +sger( 'row-major', 2, 3, 1.0, x, 1, y, 1, A, 3 ); |
| 51 | +// A => <Float32Array>[ 2.0, 3.0, 4.0, 5.0, 6.0, 7.0 ] |
| 52 | +``` |
| 53 | + |
| 54 | +The function has the following parameters: |
| 55 | + |
| 56 | +- **order**: storage layout. |
| 57 | +- **M**: number of rows in the matrix `A`. |
| 58 | +- **N**: number of columns in the matrix `A`. |
| 59 | +- **α**: scalar constant. |
| 60 | +- **x**: an `M` element [`Float32Array`][mdn-float32array]. |
| 61 | +- **sx**: stride length for `x`. |
| 62 | +- **y**: an `N` element [`Float32Array`][mdn-float32array]. |
| 63 | +- **sy**: stride length for `y`. |
| 64 | +- **A**: input matrix stored in linear memory as a [`Float32Array`][mdn-float32array]. |
| 65 | +- **lda**: stride of the first dimension of `A` (leading dimension of `A`). |
| 66 | + |
| 67 | +The stride parameters determine which elements in the strided arrays are accessed at runtime. For example, to iterate over every other element in `x` and `y`, |
| 68 | + |
| 69 | +```javascript |
| 70 | +var Float32Array = require( '@stdlib/array/float32' ); |
| 71 | + |
| 72 | +var A = new Float32Array( [ 1.0, 4.0, 2.0, 5.0, 3.0, 6.0 ] ); |
| 73 | +var x = new Float32Array( [ 1.0, 0.0, 1.0, 0.0 ] ); |
| 74 | +var y = new Float32Array( [ 1.0, 0.0, 1.0, 0.0, 1.0, 0.0 ] ); |
| 75 | + |
| 76 | +sger( 'column-major', 2, 3, 1.0, x, 2, y, 2, A, 2 ); |
| 77 | +// A => <Float32Array>[ 2.0, 5.0, 3.0, 6.0, 4.0, 7.0 ] |
| 78 | +``` |
| 79 | + |
| 80 | +Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views. |
| 81 | + |
| 82 | +<!-- eslint-disable stdlib/capitalized-comments --> |
| 83 | + |
| 84 | +```javascript |
| 85 | +var Float32Array = require( '@stdlib/array/float32' ); |
| 86 | + |
| 87 | +// Initial arrays... |
| 88 | +var x0 = new Float32Array( [ 0.0, 1.0, 1.0 ] ); |
| 89 | +var y0 = new Float32Array( [ 0.0, 1.0, 1.0, 1.0 ] ); |
| 90 | +var A = new Float32Array( [ 1.0, 4.0, 2.0, 5.0, 3.0, 6.0 ] ); |
| 91 | + |
| 92 | +// Create offset views... |
| 93 | +var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element |
| 94 | +var y1 = new Float32Array( y0.buffer, y0.BYTES_PER_ELEMENT*1 ); // start at 2nd element |
| 95 | + |
| 96 | +sger( 'column-major', 2, 3, 1.0, x1, -1, y1, -1, A, 2 ); |
| 97 | +// A => <Float32Array>[ 2.0, 5.0, 3.0, 6.0, 4.0, 7.0 ] |
| 98 | +``` |
| 99 | + |
| 100 | +#### sger.ndarray( M, N, α, x, sx, ox, y, sy, oy, A, sa1, sa2, oa ) |
| 101 | + |
| 102 | +Performs the rank 1 operation `A = α*x*y^T + A`, using alternative indexing semantics and where `α` is a scalar, `x` is an `M` element vector, `y` is an `N` element vector, and `A` is an `M` by `N` matrix. |
| 103 | + |
| 104 | +```javascript |
| 105 | +var Float32Array = require( '@stdlib/array/float32' ); |
| 106 | + |
| 107 | +var A = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] ); |
| 108 | +var x = new Float32Array( [ 1.0, 1.0 ] ); |
| 109 | +var y = new Float32Array( [ 1.0, 1.0, 1.0 ] ); |
| 110 | + |
| 111 | +sger.ndarray( 2, 3, 1.0, x, 1, 0, y, 1, 0, A, 3, 1, 0 ); |
| 112 | +// A => <Float32Array>[ 2.0, 3.0, 4.0, 5.0, 6.0, 7.0 ] |
| 113 | +``` |
| 114 | + |
| 115 | +The function has the following additional parameters: |
| 116 | + |
| 117 | +- **sa1**: stride of the first dimension of `A`. |
| 118 | +- **sa2**: stride of the second dimension of `A`. |
| 119 | +- **oa**: starting index for `A`. |
| 120 | +- **ox**: starting index for `x`. |
| 121 | +- **oy**: starting index for `y`. |
| 122 | + |
| 123 | +While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying buffer, the offset parameters support indexing semantics based on starting indices. For example, |
| 124 | + |
| 125 | +```javascript |
| 126 | +var Float32Array = require( '@stdlib/array/float32' ); |
| 127 | + |
| 128 | +var A = new Float32Array( [ 0.0, 0.0, 1.0, 4.0, 2.0, 5.0, 3.0, 6.0 ] ); |
| 129 | +var x = new Float32Array( [ 0.0, 1.0, 0.0, 1.0, 0.0 ] ); |
| 130 | +var y = new Float32Array( [ 0.0, 1.0, 0.0, 1.0, 0.0, 1.0, 0.0 ] ); |
| 131 | + |
| 132 | +sger.ndarray( 2, 3, 1.0, x, 2, 1, y, 2, 1, A, 1, 2, 2 ); |
| 133 | +// A => <Float32Array>[ 0.0, 0.0, 2.0, 5.0, 3.0, 6.0, 4.0, 7.0 ] |
| 134 | +``` |
| 135 | + |
| 136 | +</section> |
| 137 | + |
| 138 | +<!-- /.usage --> |
| 139 | + |
| 140 | +<section class="notes"> |
| 141 | + |
| 142 | +## Notes |
| 143 | + |
| 144 | +- `sger()` corresponds to the [BLAS][blas] level 2 function [`sger`][blas-sger]. |
| 145 | + |
| 146 | +</section> |
| 147 | + |
| 148 | +<!-- /.notes --> |
| 149 | + |
| 150 | +<section class="examples"> |
| 151 | + |
| 152 | +## Examples |
| 153 | + |
| 154 | +<!-- eslint no-undef: "error" --> |
| 155 | + |
| 156 | +```javascript |
| 157 | +var discreteUniform = require( '@stdlib/random/array/discrete-uniform' ); |
| 158 | +var sger = require( '@stdlib/blas/base/sger' ); |
| 159 | + |
| 160 | +var opts = { |
| 161 | + 'dtype': 'float32' |
| 162 | +}; |
| 163 | + |
| 164 | +var M = 3; |
| 165 | +var N = 5; |
| 166 | + |
| 167 | +var A = discreteUniform( M*N, 0, 255, opts ); |
| 168 | +var x = discreteUniform( M, 0, 255, opts ); |
| 169 | +var y = discreteUniform( N, 0, 255, opts ); |
| 170 | + |
| 171 | +sger( 'row-major', M, N, 1.0, x, 1, y, 1, A, N ); |
| 172 | +console.log( A ); |
| 173 | + |
| 174 | +sger.ndarray( M, N, 1.0, x, 1, 0, y, 1, 0, A, 1, M, 0 ); |
| 175 | +console.log( A ); |
| 176 | + |
| 177 | +``` |
| 178 | + |
| 179 | +</section> |
| 180 | + |
| 181 | +<!-- /.examples --> |
| 182 | + |
| 183 | +<!-- C interface documentation. --> |
| 184 | + |
| 185 | +* * * |
| 186 | + |
| 187 | +<section class="c"> |
| 188 | + |
| 189 | +## C APIs |
| 190 | + |
| 191 | +<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. --> |
| 192 | + |
| 193 | +<section class="intro"> |
| 194 | + |
| 195 | +</section> |
| 196 | + |
| 197 | +<!-- /.intro --> |
| 198 | + |
| 199 | +<!-- C usage documentation. --> |
| 200 | + |
| 201 | +<section class="usage"> |
| 202 | + |
| 203 | +### Usage |
| 204 | + |
| 205 | +```c |
| 206 | +#include "stdlib/blas/base/sger.h" |
| 207 | +``` |
| 208 | + |
| 209 | +#### c_sger( layout, M, N, alpha, \*X, strideX, \*Y, strideY, \*A, LDA ) |
| 210 | + |
| 211 | +Performs the rank 1 operation `A = alpha*x*y^T + A`, where `alpha` is a scalar, `X` is an `M` element vector, `Y` is an `N` element vector, and `A` is an `M`-by-`N` matrix. |
| 212 | + |
| 213 | +```c |
| 214 | +#include "stdlib/blas/base/shared.h" |
| 215 | + |
| 216 | +float A[ 3*4 ] = { |
| 217 | + 0.0f, 0.0f, 0.0f, 0.0f, |
| 218 | + 0.0f, 0.0f, 0.0f, 0.0f, |
| 219 | + 0.0f, 0.0f, 0.0f, 0.0f |
| 220 | +}; |
| 221 | + |
| 222 | +const float x[ 3 ] = { 1.0f, 4.0f, 0.0f }; |
| 223 | +const float y[ 4 ] = { 0.0f, 1.0f, 2.0f, 3.0f }; |
| 224 | + |
| 225 | +c_sger( CblasRowMajor, 3, 4, 1.0f, x, 1, y, 1, A, 4 ); |
| 226 | +``` |
| 227 | +
|
| 228 | +The function accepts the following arguments: |
| 229 | +
|
| 230 | +- **layout**: `[in] CBLAS_LAYOUT` storage layout. |
| 231 | +- **M**: `[in] CBLAS_INT` number of rows in the matrix `A`. |
| 232 | +- **N**: `[in] CBLAS_INT` number of columns in the matrix `A`. |
| 233 | +- **alpha**: `[in] float` scalar constant. |
| 234 | +- **X**: `[in] float*` an `M` element vector. |
| 235 | +- **strideX**: `[in] CBLAS_INT` stride length for `X`. |
| 236 | +- **Y**: `[in] float*` an `N` element vector. |
| 237 | +- **strideY**: `[in] CBLAS_INT` stride length for `Y`. |
| 238 | +- **A**: `[inout] float*` input matrix. |
| 239 | +- **LDA**: `[in] CBLAS_INT` stride of the first dimension of `A` (a.k.a., leading dimension of the matrix `A`). |
| 240 | +
|
| 241 | +```c |
| 242 | +void c_sger( const CBLAS_LAYOUT layout, const CBLAS_INT M, const CBLAS_INT N, const float alpha, const float *X, const CBLAS_INT strideX, const float *Y, const CBLAS_INT strideY, float *A, const CBLAS_INT LDA ); |
| 243 | +``` |
| 244 | + |
| 245 | +#### c_sger_ndarray( M, N, alpha, \*X, sx, ox, \*Y, sy, oy, \*A, sa1, sa2, oa ) |
| 246 | + |
| 247 | +Performs the rank 1 operation `A = alpha*x*y^T + A`, using alternative indexing semantics and where `alpha` is a scalar, `X` is an `M` element vector, `Y` is an `N` element vector, and `A` is an `M`-by-`N` matrix. |
| 248 | + |
| 249 | +```c |
| 250 | +#include "stdlib/blas/base/shared.h" |
| 251 | + |
| 252 | +float A[ 3*4 ] = { |
| 253 | + 0.0f, 0.0f, 0.0f, 0.0f, |
| 254 | + 0.0f, 0.0f, 0.0f, 0.0f, |
| 255 | + 0.0f, 0.0f, 0.0f, 0.0f |
| 256 | +}; |
| 257 | + |
| 258 | +const float x[ 3 ] = { 1.0f, 4.0f, 0.0f }; |
| 259 | +const float y[ 4 ] = { 0.0f, 1.0f, 2.0f, 3.0f }; |
| 260 | + |
| 261 | +c_sger_ndarray( 3, 4, 1.0f, x, 1, 0, y, 1, 0, A, 4, 1, 0 ); |
| 262 | +``` |
| 263 | +
|
| 264 | +The function accepts the following arguments: |
| 265 | +
|
| 266 | +- **layout**: `[in] CBLAS_LAYOUT` storage layout. |
| 267 | +- **M**: `[in] CBLAS_INT` number of rows in the matrix `A`. |
| 268 | +- **N**: `[in] CBLAS_INT` number of columns in the matrix `A`. |
| 269 | +- **alpha**: `[in] float` scalar constant. |
| 270 | +- **X**: `[in] float*` an `M` element vector. |
| 271 | +- **sx**: `[in] CBLAS_INT` stride length for `X`. |
| 272 | +- **ox**: `[in] CBLAS_INT` starting index for `X`. |
| 273 | +- **Y**: `[in] float*` an `N` element vector. |
| 274 | +- **sy**: `[in] CBLAS_INT` stride length for `Y`. |
| 275 | +- **oy**: `[in] CBLAS_INT` starting index for `Y`. |
| 276 | +- **A**: `[inout] float*` input matrix. |
| 277 | +- **sa1**: `[in] CBLAS_INT` stride of the first dimension of `A`. |
| 278 | +- **sa2**: `[in] CBLAS_INT` stride of the second dimension of `A`. |
| 279 | +- **oa**: `[in] CBLAS_INT` starting index for `A`. |
| 280 | +
|
| 281 | +```c |
| 282 | +void c_sger( onst CBLAS_INT M, const CBLAS_INT N, const float alpha, const float *X, const CBLAS_INT strideX, const CBLAS_INT offsetX, const float *Y, const CBLAS_INT strideY, const CBLAS_INT offsetY, float *A, const CBLAS_INT strideA1, const CBLAS_INT strideA2, const CBLAS_INT offsetA ); |
| 283 | +``` |
| 284 | + |
| 285 | +</section> |
| 286 | + |
| 287 | +<!-- /.usage --> |
| 288 | + |
| 289 | +<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. --> |
| 290 | + |
| 291 | +<section class="notes"> |
| 292 | + |
| 293 | +</section> |
| 294 | + |
| 295 | +<!-- /.notes --> |
| 296 | + |
| 297 | +<!-- C API usage examples. --> |
| 298 | + |
| 299 | +<section class="examples"> |
| 300 | + |
| 301 | +### Examples |
| 302 | + |
| 303 | +```c |
| 304 | +#include "stdlib/blas/base/sger.h" |
| 305 | +#include "stdlib/blas/base/shared.h" |
| 306 | +#include <stdio.h> |
| 307 | + |
| 308 | +int main( void ) { |
| 309 | + // Define a 3x4 matrix stored in row-major order: |
| 310 | + float A[ 3*4 ] = { |
| 311 | + 0.0f, 0.0f, 0.0f, 0.0f, |
| 312 | + 0.0f, 0.0f, 0.0f, 0.0f, |
| 313 | + 0.0f, 0.0f, 0.0f, 0.0f |
| 314 | + }; |
| 315 | + // Define `x` and `y^T` vectors: |
| 316 | + const float x[ 3 ] = { 1.0f, 4.0f, 0.0f }; // M |
| 317 | + const float y[ 4 ] = { 0.0f, 1.0f, 2.0f, 3.0f }; // N |
| 318 | + |
| 319 | + // Specify the number of rows and columns: |
| 320 | + const int M = 3; |
| 321 | + const int N = 4; |
| 322 | + |
| 323 | + // Specify stride lengths: |
| 324 | + const int strideX = 1; |
| 325 | + const int strideY = 1; |
| 326 | + |
| 327 | + // Perform operation: |
| 328 | + c_sger( CblasRowMajor, M, N, 1.0f, x, strideX, y, strideY, A, N ); |
| 329 | + |
| 330 | + // Print the result: |
| 331 | + for ( int i = 0; i < M; i++ ) { |
| 332 | + for ( int j = 0; j < N; j++ ) { |
| 333 | + printf( "A[%i,%i] = %f\n", i, j, A[ (i*N)+j ] ); |
| 334 | + } |
| 335 | + } |
| 336 | + |
| 337 | + // Perform operation using alterntive indexing semantics: |
| 338 | + c_sger( CblasRowMajor, M, N, 1.0f, x, strideX, 0, y, 0, strideY, A, N, 1, 0 ); |
| 339 | + |
| 340 | + // Print the result: |
| 341 | + for ( int i = 0; i < M; i++ ) { |
| 342 | + for ( int j = 0; j < N; j++ ) { |
| 343 | + printf( "A[%i,%i] = %f\n", i, j, A[ (i*N)+j ] ); |
| 344 | + } |
| 345 | + } |
| 346 | +} |
| 347 | +``` |
| 348 | +
|
| 349 | +</section> |
| 350 | +
|
| 351 | +<!-- /.examples --> |
| 352 | +
|
| 353 | +</section> |
| 354 | +
|
| 355 | +<!-- /.c --> |
| 356 | +
|
| 357 | +<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. --> |
| 358 | +
|
| 359 | +<section class="related"> |
| 360 | +
|
| 361 | +</section> |
| 362 | +
|
| 363 | +<!-- /.related --> |
| 364 | +
|
| 365 | +<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. --> |
| 366 | +
|
| 367 | +<section class="links"> |
| 368 | +
|
| 369 | +[blas]: http://www.netlib.org/blas |
| 370 | +
|
| 371 | +[blas-sger]: https://www.netlib.org/lapack/explore-html/d8/d75/group__ger_ga95baec6bb0a84393d7bc67212b566ab0.html |
| 372 | +
|
| 373 | +[mdn-float32array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array |
| 374 | +
|
| 375 | +[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray |
| 376 | +
|
| 377 | +</section> |
| 378 | +
|
| 379 | +<!-- /.links --> |
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