Possible Crash in QR

[benjojo]

When writing a tool to generate polynormials I have encountered a bug where the libary would crash in QR and take the whole program with it.

You can find the code I used: https://github.com/playgenhub/DataPlay/blob/master/tools/generatepolys/gen.go#L13

Here is the stack trace:

panic: runtime error: slice bounds out of range

goroutine 1 [running]:
github.com/skelterjohn/go%2ematrix.(*DenseMatrix).QR(0xc0801f6ae0, 0x1, 0xc0801f6bd0,0xc0801f6c30)
        C:/Users/Ben Cox/src/github.com/skelterjohn/go.matrix/dense_decomp.go:177 +0x12bb
main.GetPolyResults(0xc0802bdf60, 0x2, 0x2, 0xc0802bdf70, 0x2, ...)
        C:/Users/Ben Cox/Documents/datacon/tools/generatepolys/gen.go:35 +0x306
main.DoPoly(0xc0801a0140, 0x3f, 0xc0800d79c0, 0x12, 0xc0800af8c0, ...)
        C:/Users/Ben Cox/Documents/datacon/tools/generatepolys/gen.go:116 +0x4dc

main.main()
        C:/Users/Ben Cox/Documents/datacon/tools/generatepolys/gen.go:100 +0xb54

I put a trap into the library to capture the state before it crashed:

func (A *DenseMatrix) QR(debug bool) (Q, R *DenseMatrix) {
    if debug {
        b, _ := json.Marshal(A.elements)
        fmt.Println(string(b))
    }

And I got this back when the application would crash

[
  1,
  21669,
  469545561,
  1,
  1447,
  2093809
]

if it is any help the dataset that was shoved into it was:

transaction_number,ap_amount____
149149,27589.1
149166,30032
161184,1797250
161691,27066.7
169567,25706.4
161186,1134340
161756,90027
161188,132034
161190,693800
161180,222737
161665,26729
206584,30528
161696,29500.2
193463,92318
178295,304469
161192,2182670
184579,78657.1
161718,30097.2