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* @license Apache-2.0
*
* Copyright (c) 2025 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
// MODULES //
var isLayout = require( '@stdlib/blas/base/assert/is-layout' );
var isRowMajor = require( '@stdlib/ndarray/base/assert/is-row-major-string' );
var isColumnMajor = require( '@stdlib/ndarray/base/assert/is-column-major-string' );
var max = require( '@stdlib/math/base/special/max' );
var format = require( '@stdlib/string/format' );
var isOperation = require( './isoperation.js' );
var NORMS = require( './norms.json' ).norms;
var base = require( './base.js' );
// MAIN //
/**
* Returns the value of the one norm, or the frobenius norm, or the infinity norm, or the element with the largest absolute value of a real matrix `A`.
*
* ## Notes
*
* - use `norm` = `max` to calculate the element with the largest absolute value
* - use `norm` = `one` to calculate the one norm, work should have `N` indexed elements if row-major layout is used
* - use `norm` = `infinity` to calculate the infinity norm, work should have `M` indexed elements if column-major layout is used
* - use `norm` = `frobenius` to calculate the frobenius norm
*
* @private
* @param {string} order - storage layout
* @param {string} norm - specifies the type of norm to be calculated
* @param {NonNegativeInteger} M - number of rows in `A`
* @param {NonNegativeInteger} N - number of columns in `A`
* @param {Float64Array} A - input array
* @param {PositiveInteger} LDA - stride of the first dimension of `A` (a.k.a., leading dimension of the matrix `A`)
* @param {Float64Array} work - temporary workspace array
* @throws {TypeError} first argument must be a valid order
* @throws {TypeError} second argument must be a valid operation
* @throws {RangeError} sixth argument must be greater than or equal to max(1,N)
* @returns {number} required norm value
*
* @example
* var Float64Array = require( '@stdlib/array/float64' );
*
* var A = new Float64Array( [ 1.0, 4.0, 7.0, 10.0, 2.0, 5.0, 8.0, 11.0, 3.0, 6.0, 9.0, 12.0 ] );
* var work = new Float64Array( 3 );
*
* var out = dlange( 'row-major', 'frobenius', 3, 4, A, 4, work );
* // returns ~25.5
*/
function dlange( order, norm, M, N, A, LDA, work ) {
var sa1;
var sa2;
if ( !isLayout( order ) ) {
throw new TypeError( format( 'invalid argument. First argument must be a valid order. Value: `%s`.', order ) );
}
if ( !isOperation( norm ) ) {
throw new TypeError( format( 'invalid argument. Second argument must be one of the following: "%s". Value: `%s`.', NORMS.join( '", "' ), norm ) );
}
if ( isRowMajor( order ) && LDA < max( 1, N ) ) {
throw new RangeError( format( 'invalid argument. Sixth argument must be greater than or equal to max(1,%d). Value: `%d`.', N, LDA ) );
}
if ( isColumnMajor( order ) ) {
sa1 = 1;
sa2 = LDA;
} else { // order === 'row-major'
sa1 = LDA;
sa2 = 1;
}
return base( norm, M, N, A, sa1, sa2, 0, work, 1, 0 );
}
// EXPORTS //
module.exports = dlange;
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