﻿ILMath.linsolveTriUp Method (InArray(fcomplex), InArray(fcomplex), Int32)

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Solve system of linear equations A*x = B, with A being a square, upper triangular matrix.

[ILNumerics Computing Engine]

Namespace:  ILNumerics
Assembly:  ILNumerics.Computing (in ILNumerics.Computing.dll) Version: 5.5.0.0 (5.5.7503.3146)
Syntax

```public static RetArray<fcomplex> linsolveTriUp(
InArray<fcomplex> A,
InArray<fcomplex> B,
ref int singularityDetect
)```

#### Parameters

A
Type: ILNumericsInArrayfcomplex
Input matrix. Size [n,n]. Upper triangular. No check is made for that!
B
Type: ILNumericsInArrayfcomplex
Right hand side vector /matrix. Size [n,m].
singularityDetect
Type: SystemInt32
[Output] This value gives the row of A, where a singularity has been detected (if any). If A is not singular, this will return a negative value.

#### Return Value

Type: RetArrayfcomplex
Solution x solving A * x = B. Size [n,m].
Remarks

The solution is determined via backward substitution by using a native LAPACK module.

Make sure, A and B are of correct size, since no checks are made for that!

This function is used by linsolve(InArrayfcomplex, InArrayfcomplex, MatrixProperties, Boolean). It can speed up the computation for known, matching matrices, since it saves some checks on them which are otherwise automatically performed by linsolve(InArrayfcomplex, InArrayfcomplex, MatrixProperties, Boolean).

Any elements of A located below the main diagonal will be ignored.

If A is singular the array returned contains NaN values.

[ILNumerics Computing Engine]