ARPACKException: unspecified ARPACK error: 3

[KenZhenLin]

Hi,
I have got the following error while using TRS: "ARPACKException: unspecified ARPACK error: 3". The complete error message is so long that I didn't paste it here. The Julia code that will generate the error is attached below:

`using TRS

Bt = zeros(50,50)
qt = zeros(50)
rt = 1.0523395162521898 # trust region radius

assign elements to vector qt and matrix Bt

id_qt = [1
25
38
50]

qt[id_qt] = [0.4001448785635572
0.37625698660860646
0.36390248362433253
0.7522564314112639]

id_Bt = [CartesianIndex(1, 1)
CartesianIndex(38, 1)
CartesianIndex(50, 1)
CartesianIndex(11, 11)
CartesianIndex(16, 11)
CartesianIndex(50, 11)
CartesianIndex(11, 16)
CartesianIndex(16, 16)
CartesianIndex(50, 16)
CartesianIndex(17, 17)
CartesianIndex(50, 17)
CartesianIndex(25, 25)
CartesianIndex(50, 25)
CartesianIndex(31, 31)
CartesianIndex(50, 31)
CartesianIndex(1, 38)
CartesianIndex(38, 38)
CartesianIndex(1, 50)
CartesianIndex(11, 50)
CartesianIndex(16, 50)
CartesianIndex(17, 50)
CartesianIndex(25, 50)
CartesianIndex(31, 50)
CartesianIndex(50, 50)]

Bt[id_Bt] = [ 0.9421322478303554
0.3997653759456624
0.406303572599046
0.9969200943572806
0.39513821340999916
-0.46843465642026494
0.39513821340999916
0.8385542855877862
-0.4395534582065728
0.8162248904915448
0.5155255881440579
0.7870742895465026
0.6471710137803152
0.8357458508870682
-0.5025733395283566
0.3997653759456624
0.8036342938547227
0.406303572599046
-0.46843465642026494
-0.4395534582065728
0.5155255881440579
0.6471710137803152
-0.5025733395283566
2.2650759260526083 ]

run trs for a few times

for T = 1:100
pt, infot = trs(Bt, qt, rt)
end`

The error doesn't occur every time when calling trs with the data above. Therefore, I run trs for 100 times in this code to make sure the error occurs.

I would appreciate it if you could help me deal with this issue. Thanks in advance.