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CMSIS-DSP/PythonWrapper/examples/example_1_5.py

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Python

# New functions for version 1.5 of the Python wrapper
import cmsisdsp as dsp
import cmsisdsp.fixedpoint as f
import numpy as np
import math
import colorama
from colorama import init,Fore, Back, Style
from numpy.testing import assert_allclose
from numpy.linalg import qr
def householder(x,eps=1e-16):
#print(x)
v=np.hstack([[1],x[1:]])
alpha = x[0]
xnorm2=x[1:].dot(x[1:])
epsilon=eps
#print(sigma)
if xnorm2<=epsilon:
tau = 0.0
v = np.zeros(len(x))
else:
if np.sign(alpha) <= 0:
beta = math.sqrt(alpha*alpha + xnorm2)
else:
beta = -math.sqrt(alpha*alpha + xnorm2)
r = (alpha - beta)
v = x / r
tau = (beta - alpha) / beta
v[0] = 1
return(v,tau)
init()
def printTitle(s):
print("\n" + Fore.GREEN + Style.BRIGHT + s + Style.RESET_ALL)
def printSubTitle(s):
print("\n" + Style.BRIGHT + s + Style.RESET_ALL)
printTitle("Householder")
VECDIM = 10
a=np.random.randn(VECDIM)
a = a / np.max(np.abs(a))
# Reference
vRef,betaRef = householder(a)
printSubTitle("Householder F32")
betaF32,vF32 = dsp.arm_householder_f32(a,dsp.DEFAULT_HOUSEHOLDER_THRESHOLD_F32)
print(np.isclose(betaRef,betaF32,1e-6,1e-6))
print(np.isclose(vRef,vF32,1e-6,1e-6))
printSubTitle("Householder F64")
betaF64,vF64 = dsp.arm_householder_f64(a,dsp.DEFAULT_HOUSEHOLDER_THRESHOLD_F64)
print(np.isclose(betaRef,betaF64,1e-6,1e-6))
print(np.isclose(vRef,vF64,1e-6,1e-6))
printSubTitle("Householder Proportional F32")
a=np.random.randn(5)
# With the threshold defined with DEFAULT_HOUSEHOLDER_THRESHOLD_F32
# this vector is considered as proportional to (1,0,...)
# and thus the function will return (0,[0,...,0])
a = a / np.max(np.abs(a)) * 1.0e-7
resF32 = dsp.arm_householder_f32(a,dsp.DEFAULT_HOUSEHOLDER_THRESHOLD_F32)
print(resF32)
# With a smaller threshold, a computation is taking place
resF32 = dsp.arm_householder_f32(a,0.001*dsp.DEFAULT_HOUSEHOLDER_THRESHOLD_F32)
print(resF32)
printTitle("QR decomposition")
def checkOrtho(A,err=1e-10):
product = A.T.dot(A)
#print(A)
np.fill_diagonal(product,0)
#print(product)
print(np.max(np.abs(product)))
return (np.all(np.abs(product)<=err))
rows = 8
columns = 5
def randomIsometry(rows,cols,rank):
if rank==1:
r=np.random.randn(rows)
r = Tools.normalize(r)[np.newaxis]
c=np.random.randn(cols)
c = Tools.normalize(c)[np.newaxis]
result=r.T.dot(c)
else:
a = np.random.randn(rows,rows)
b = np.random.randn(cols,cols)
diagDim = min(rows,cols)
d = np.zeros((rows,cols))
diag = np.ones(diagDim)
diag[rank:] = 0
np.fill_diagonal(d,diag)
qa,_ = qr(a)
qb,_ = qr(b)
result = qa .dot(d.dot(qb))
return(result)
m = randomIsometry(rows,columns,columns-1)
rows,columns = m.shape
# The CMSIS-DSP C functions is requiring two temporary arrays
# To follow the C function as closely as possible, we create
# two arrays. Their size will be used internally by the Python
# wrapper to allocate two temporary buffers.
# Like that you can check you have dimensionned the arrays in the
# right way.
# The content of the temporary buffers is not accesible from the
# Python API. tmpa and tmpb are not modified.
tmpa=np.zeros(rows)
tmpb=np.zeros(rows)
printSubTitle("QR F64")
status,r,q,tau = dsp.arm_mat_qr_f64(m,dsp.DEFAULT_HOUSEHOLDER_THRESHOLD_F64,tmpa,tmpb)
# Status different from 0 if matrix dimensions are not right
# (rows must be >= columns)
#print(status)
#print(q)
#print(r)
#print(tau)
# Check that the matrix Q is orthogonal
assert(checkOrtho(q,err=1e-14))
# Remove householder vectors from R matrix
i=1
for c in r.T:
c[i:] = 0
i = i+1
# Check that M = Q R
newm = np.dot(q,r)
assert_allclose(newm,m)
printSubTitle("QR F32")
status,r,q,tau = dsp.arm_mat_qr_f32(m,dsp.DEFAULT_HOUSEHOLDER_THRESHOLD_F32,tmpa,tmpb)
# Status different from 0 if matrix dimensions are not right
# (rows must be >= columns)
#print(status)
#print(q)
#print(r)
#print(tau)
# Check that the matrix Q is orthogonal
assert(checkOrtho(q,err=1.0e-6))
# Remove householder vectors from R matrix
i=1
for c in r.T:
c[i:] = 0
i = i+1
# Check that M = Q R
newm = np.dot(q,r)
assert_allclose(newm,m,2e-6,1e-7)