# problems using inverse

• Subject: problems using inverse
• From: " Albrecht Weerts" <Albrecht.Weerts@wldelft.nl>
• Date: Wed, 7 Apr 2004 16:48:11 +0200
• Content-Transfer-Encoding: 7bit
• Content-Type: text/plain; charset="iso-8859-1"
• Reply-To: " Albrecht Weerts" <Albrecht.Weerts@wldelft.nl>

```
Started using Jama a few months ago but now running into some probelms

Inverting this matrix with jama
A1=
0.18912803726394   0.16034537535266   0.07602040927109
0.16034537535266   0.14266722113336   0.08046930838699
0.07602040927109   0.08046930838699   0.14469936354505

yields a singular matrix  (A1.inverse())
but with Matlab it yields
inv(A1)=

1.0e+002 *

1.46623175989361  -1.76799577416819   0.21289560610586
-1.76799577416819   2.23399278022841  -0.31350581311000
0.21289560610586  -0.31350581311000   0.13160517352345

Can you tell me why this occurs or am I doing something wrong?

Sincerely,

Albrecht Weerts

see error message:

A1:0.18912803726393707
A1:0.16034537535265792
A1:0.07602040927108947
A1:0.16034537535265792
A1:0.14266722113335908
A1:0.0804693083869916
A1:0.07602040927108947
A1:0.0804693083869916
A1:0.14469936354505025
Exception in thread "main" java.lang.RuntimeException: Matrix is singular.
at Jama.LUDecomposition.solve(LUDecomposition.java:282)
at Jama.Matrix.solve(Matrix.java:815)
at Jama.Matrix.inverse(Matrix.java:833)
at dud.<init>(Cal.java:226)
at Cal.main(Cal.java:138)

-----------------------------------------------------------------
Dr. A. H. Weerts
WL|Delft Hydraulics
P.O. Box 177
2600 MH Delft
The Netherlands

email. albrecht.weerts@wldelft.nl

tel. +31-(0)15-2858922
fax. +31-(0)15-2858582

url: http://www.wldelft.nl/
------------------------------------------------------------------

```

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