83 lines
1.3 KiB
Go
83 lines
1.3 KiB
Go
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package stats
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import (
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"errors"
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"log"
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"gonum.org/v1/gonum/mat"
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)
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func rotateFloats(f []float64, n int) []float64 {
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flen := len(f)
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if n < 0 || flen == 0 {
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return f
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}
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r := flen - n%flen
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f = append(f[r:], f[:r]...)
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return f
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}
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func constructMatrix(f []float64) ([][]float64, error) {
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flen := len(f)
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if flen < 1 {
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return nil, errors.New("ErrSliceZeroLength")
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}
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m := make([][]float64, 0, flen)
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// add first row unchanged.
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m = append(m, f)
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rot := rotateFloats(f, 1)
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for i := 0; i < flen-1; i++ {
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m = append(m, rot)
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rot = rotateFloats(rot, 1)
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}
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return m, nil
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}
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func invertMatrix(m [][]float64, size int) (*mat.Dense, error) {
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flM := []float64{}
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for i := range m {
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flM = append(flM, m[i]...)
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}
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a := mat.NewDense(size, size, flM)
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// compute the inverse of A, if possible.
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var aInv mat.Dense
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err := aInv.Inverse(a)
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if err != nil {
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log.Print("matrix is not invertible")
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return nil, errors.New("matrix is not invertible")
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}
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return &aInv, nil
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}
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func estimateImpulseFunc(gMat mat.Dense, lruu int) ([]float64, error) {
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g := gMat.RawMatrix().Data
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lenG := len(g)
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if lenG != lruu {
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return nil, errors.New("ErrLenGDiffersFromLRuu")
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}
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h := make([]float64, lenG)
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// set first elem manually.
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h[0] = g[0]
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for i := 1; i < lenG; i++ {
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h[i] = h[i-1] + g[i]
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}
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return h, nil
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}
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