refactor: forbenius norm implementation and tests

stdlib-js · Aug 1, 2024 · b0742ba · b0742ba
1 parent 94d1264
commit b0742ba
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diff --git a/lib/node_modules/@stdlib/lapack/base/dlange/lib/base.js b/lib/node_modules/@stdlib/lapack/base/dlange/lib/base.js
@@ -25,8 +25,8 @@
 var isRowMajor = require( '@stdlib/ndarray/base/assert/is-row-major' );
 var dlassq = require( '@stdlib/lapack/base/dlassq' ).ndarray;
 var lowercase = require( '@stdlib/string/base/lowercase' );
+var dnrm2 = require( '@stdlib/blas/base/dnrm2' ).ndarray;
 var sqrt = require( '@stdlib/math/base/special/sqrt' );
-var Float64Array = require( '@stdlib/array/float64' );
 var abs = require( '@stdlib/math/base/special/abs' );
 var min = require( '@stdlib/math/base/special/min' );
 var isnan = require( '@stdlib/assert/is-nan' );
@@ -192,27 +192,34 @@ function infNorm( M, N, A, strideA1, strideA2, offsetA, work, strideW, offsetW )
 * @param {integer} strideA1 - stride of the first dimension of `A`
 * @param {integer} strideA2 - stride of the second dimension of `A`
 * @param {PositiveInteger} offsetA - starting index for `A`
+* @param {Float64Array} work - workspace array
+* @param {integer} strideW - stride length for `work`
+* @param {PositiveInteger} offsetW - starting index for `work`
 * @returns {number} Frobenius norm
 *
 * @example
 * var Float64Array = require( '@stdlib/array/float64' );
 *
 * var A = new Float64Array( [ 1.0, 2.0, 3.0, 4.0 ] );
+* var work = new Float64Array( 2 );
 *
-* var out = frobeniusNorm( 2, 2, A, 2, 1, 0 );
+* var out = frobeniusNorm( 2, 2, A, 2, 1, 0, work, 1, 0 );
 * // returns 5.477225575051661
 */
-function frobeniusNorm( M, N, A, strideA1, strideA2, offsetA ) {
+function frobeniusNorm( M, N, A, strideA1, strideA2, offsetA, work, strideW, offsetW ) {
  var value;
- var out;
  var j;
 
  // Find normF( A )
- out = new Float64Array( [ 0.0, 1.0 ] );
+ if ( M === 1 ) {
+ return dnrm2( N, A, strideA2, offsetA, strideA1 );
+ }
+ work[ offsetW ] = 0.0;
+ work[ offsetW + strideW ] = 1.0;
  for ( j = 0; j < N; j++ ) {
- out = dlassq( M, A, strideA1, offsetA + ( j * strideA2 ), out[ 0 ], out[ 1 ], out, 1, 0 );
+ work = dlassq( M, A, strideA1, offsetA + ( j * strideA2 ), work[ offsetW ], work[ offsetW + strideW ], work, strideW, offsetW );
  }
- value = out[ 0 ] * sqrt( out[ 1 ] );
+ value = work[ offsetW ] * sqrt( work[ offsetW + strideW ] );
  return value;
 }
 
@@ -246,7 +253,6 @@ function frobeniusNorm( M, N, A, strideA1, strideA2, offsetA ) {
 */
 function dlange( norm, M, N, A, strideA1, strideA2, offsetA, work, strideW, offsetW ) {
  var order;
- var value;
 
  norm = lowercase( norm );
  if ( isRowMajor( [ strideA1, strideA2 ] ) ) {
@@ -256,8 +262,9 @@ function dlange( norm, M, N, A, strideA1, strideA2, offsetA, work, strideW, offs
  }
 
  if ( min( M, N ) === 0.0 ) {
- value = 0.0;
- } else if ( norm === 'm' ) {
+ return 0.0;
+ }
+ if ( norm === 'm' ) {
  return maxAbsNorm( order, M, N, A, strideA1, strideA2, offsetA );
  }
  if ( norm === 'o' || norm === '1' ) {
@@ -267,9 +274,8 @@ function dlange( norm, M, N, A, strideA1, strideA2, offsetA, work, strideW, offs
  return infNorm( M, N, A, strideA1, strideA2, offsetA, work, strideW, offsetW );
  }
  if ( norm === 'f' ) {
- return frobeniusNorm( M, N, A, strideA1, strideA2, offsetA );
+ return frobeniusNorm( M, N, A, strideA1, strideA2, offsetA, work, strideW, offsetW );
  }
- return value;
 }
 
 

diff --git a/lib/node_modules/@stdlib/lapack/base/dlange/test/test.dlange.js b/lib/node_modules/@stdlib/lapack/base/dlange/test/test.dlange.js
@@ -77,7 +77,6 @@ tape( 'the function returns maximum absolute value of elements of a square real
 
  out = dlange( 'row-major', 'M', 2, 2, A, 2, work );
  expected = 4.0;
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -93,7 +92,6 @@ tape( 'the function returns maximum absolute value of elements of a real matrix
 
  out = dlange( 'row-major', 'M', 2, 3, A, 3, work );
  expected = 6.0;
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -109,7 +107,6 @@ tape( 'the function returns maximum absolute value of elements of a square real
 
  out = dlange( 'column-major', 'M', 2, 2, A, 2, work );
  expected = 4.0;
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -125,7 +122,6 @@ tape( 'the function returns maximum absolute value of elements of a real matrix
 
  out = dlange( 'column-major', 'M', 3, 2, A, 2, work );
  expected = 6.0;
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -141,15 +137,12 @@ tape( 'the function returns the one norm of a square real matrix ( row-major )',
 
  out = dlange( 'row-major', '1', 2, 2, A, 2, work );
  expected = 6.0;
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'row-major', 'O', 2, 2, A, 2, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'row-major', 'o', 2, 2, A, 2, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -165,15 +158,12 @@ tape( 'the function returns the one norm of a real matrix ( row-major )', functi
 
  out = dlange( 'row-major', '1', 2, 3, A, 3, work );
  expected = 9.0;
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'row-major', 'O', 2, 3, A, 3, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'row-major', 'o', 2, 3, A, 3, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -189,15 +179,12 @@ tape( 'the function returns the one norm of a square real matrix ( column-major
 
  out = dlange( 'column-major', '1', 2, 2, A, 2, work );
  expected = 6.0;
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'column-major', 'O', 2, 2, A, 2, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'column-major', 'o', 2, 2, A, 2, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -213,15 +200,12 @@ tape( 'the function returns the one norm of a real matrix ( column-major )', fun
 
  out = dlange( 'column-major', '1', 3, 2, A, 2, work );
  expected = 10.0;
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'column-major', 'O', 3, 2, A, 2, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'column-major', 'o', 3, 2, A, 2, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -237,11 +221,9 @@ tape( 'the function returns the infinity norm of a square real matrix ( row-majo
 
  out = dlange( 'row-major', 'I', 2, 2, A, 2, work );
  expected = 7.0;
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'row-major', 'i', 2, 2, A, 2, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -257,11 +239,9 @@ tape( 'the function returns the infinity norm of a real matrix ( row-major )', f
 
  out = dlange( 'row-major', 'I', 2, 3, A, 3, work );
  expected = 15.0;
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'row-major', 'i', 2, 3, A, 3, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -277,11 +257,9 @@ tape( 'the function returns the infinity norm of a square real matrix ( column-m
 
  out = dlange( 'column-major', 'I', 2, 2, A, 2, work );
  expected = 7.0;
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'column-major', 'i', 2, 2, A, 2, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -297,11 +275,9 @@ tape( 'the function returns the infinity norm of a real matrix ( column-major )'
 
  out = dlange( 'column-major', 'I', 3, 2, A, 2, work );
  expected = 9.0;
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'column-major', 'i', 3, 2, A, 2, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -317,11 +293,13 @@ tape( 'the function returns the Frobenius norm of a square real matrix ( row-maj
 
  out = dlange( 'row-major', 'F', 2, 2, A, 2, work );
  expected = 5.477225575051661;
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'row-major', 'f', 2, 2, A, 2, work );
+ t.strictEqual( out, expected, 'returns expected value' );
 
+ work = new Float64Array( 1 );
+ out = dlange( 'row-major', 'F', 1, 4, A, 4, work );
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -337,11 +315,9 @@ tape( 'the function returns the Frobenius norm of a real matrix ( row-major )',
 
  out = dlange( 'row-major', 'F', 2, 3, A, 3, work );
  expected = 9.539392014169456;
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'row-major', 'f', 2, 3, A, 3, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -357,11 +333,9 @@ tape( 'the function returns the Frobenius norm of a square real matrix ( column-
 
  out = dlange( 'column-major', 'F', 2, 2, A, 2, work );
  expected = 5.477225575051661;
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'column-major', 'f', 2, 2, A, 2, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });
@@ -377,11 +351,9 @@ tape( 'the function returns the Frobenius norm of a real matrix ( column-major )
 
  out = dlange( 'column-major', 'F', 3, 2, A, 2, work );
  expected = 7.681145747868608;
-
  t.strictEqual( out, expected, 'returns expected value' );
 
  out = dlange( 'column-major', 'f', 3, 2, A, 2, work );
-
  t.strictEqual( out, expected, 'returns expected value' );
  t.end();
 });