1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
package dstream
import "fmt"
type linapply struct {
xform
coeffs [][]float64
basename string
}
func (a *linapply) init() {
snames := a.source.Names()
names := make([]string, len(snames), len(snames)+len(a.coeffs))
copy(names, snames)
for j := 0; j < len(a.coeffs); j++ {
names = append(names, fmt.Sprintf("%s%d", a.basename, j))
}
a.names = names
a.bdata = make([]interface{}, len(a.names))
}
// Linapply adds new variables to Dstream by taking linear
// combinations of the other variables in the Dstream.
func Linapply(data Dstream, coeffs [][]float64, basename string) Dstream {
a := &linapply{
xform: xform{
source: data,
},
coeffs: coeffs,
basename: basename,
}
a.init()
return a
}
func (a *linapply) Next() bool {
f := a.source.Next()
if !f {
return false
}
// Copy the existing variables directly
for j := 0; j < a.source.NumVar(); j++ {
a.bdata[j] = a.source.GetPos(j)
}
n := ilen(a.GetPos(0))
q := a.source.NumVar()
// Loop over new variables to create
for j, v := range a.coeffs {
if len(v) != q {
msg := fmt.Sprintf("coefs (d=%d) does not conform with variables (d=%d)", len(v), q)
panic(msg)
}
// Create space for new variable
var z []float64
if a.bdata[q+j] != nil {
z = a.bdata[q+j].([]float64)
}
z = resizeFloat64(z, n)
a.bdata[q+j] = z
zeroFloat(z)
// Loop over summands
for k := 0; k < q; k++ {
switch x := a.bdata[k].(type) {
case []float64:
for i := range z {
z[i] += v[k] * x[i]
}
case []string:
// do nothing
default:
panic("unknown type")
}
}
}
return true
}
|
