How to apply this linear transformation $(x:=2x+1)$ on R-sequence result to generate points in range...












0












$begingroup$


I want to used R-sequence proposed by Martin Roberts to generate points in range [-1,1].
In this post, Martin Roberts mentioned that:




... to convert to a range of [-1,1], simply apply the linear
transformation x:=2x+1. The result is



(-0.361655, -0.657913, -0.900599)



(-0.72331, 0.684174, 0.198802)



(0.915035, 0.0262616, -0.701797)



(0.55338, -0.631651, 0.397604)



(0.191725, 0.710436, -0.502995),...




I am not specialist in math, I just want to know how to apply this transformation to generate points in range [-1,1]?
and in which part of the provided code?



This code generates points in range [0,1]



# Use Newton-Rhapson-Method
def gamma(d):
x=1.0000
for i in range(20):
x = x-(pow(x,d+1)-x-1)/((d+1)*pow(x,d)-1)
return x

d=3
n=5

g = gamma(d)
alpha = np.zeros(d)
for j in range(d):
alpha[j] = pow(1/g,j+1) %1
z = np.zeros((n, d))
for i in range(n):
z = (0.5 + alpha*(i+1)) %1

print(z)


The result is:



(0.319173, 0.171044, 0.0497005)
(0.138345, 0.842087, 0.599401)
(0.957518, 0.513131, 0.149101)
(0.77669, 0.184174, 0.698802)
(0.595863, 0.855218, 0.248502) ...


How to apply this linear transformation x:=2x+1 to get this result:



(-0.361655, -0.657913, -0.900599)
(-0.72331, 0.684174, 0.198802)
(0.915035, 0.0262616, -0.701797)
(0.55338, -0.631651, 0.397604)
(0.191725, 0.710436, -0.502995),...









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  • $begingroup$
    Please try to make the titles of your questions more informative. For example, Why does $a<b$ imply $a+c<b+c$? is much more useful for other users than A question about inequality. From How can I ask a good question?: Make your title as descriptive as possible. In many cases one can actually phrase the title as the question, at least in such a way so as to be comprehensible to an expert reader. You can find more tips for choosing a good title here.
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    – Shaun
    Dec 8 '18 at 11:56
















0












$begingroup$


I want to used R-sequence proposed by Martin Roberts to generate points in range [-1,1].
In this post, Martin Roberts mentioned that:




... to convert to a range of [-1,1], simply apply the linear
transformation x:=2x+1. The result is



(-0.361655, -0.657913, -0.900599)



(-0.72331, 0.684174, 0.198802)



(0.915035, 0.0262616, -0.701797)



(0.55338, -0.631651, 0.397604)



(0.191725, 0.710436, -0.502995),...




I am not specialist in math, I just want to know how to apply this transformation to generate points in range [-1,1]?
and in which part of the provided code?



This code generates points in range [0,1]



# Use Newton-Rhapson-Method
def gamma(d):
x=1.0000
for i in range(20):
x = x-(pow(x,d+1)-x-1)/((d+1)*pow(x,d)-1)
return x

d=3
n=5

g = gamma(d)
alpha = np.zeros(d)
for j in range(d):
alpha[j] = pow(1/g,j+1) %1
z = np.zeros((n, d))
for i in range(n):
z = (0.5 + alpha*(i+1)) %1

print(z)


The result is:



(0.319173, 0.171044, 0.0497005)
(0.138345, 0.842087, 0.599401)
(0.957518, 0.513131, 0.149101)
(0.77669, 0.184174, 0.698802)
(0.595863, 0.855218, 0.248502) ...


How to apply this linear transformation x:=2x+1 to get this result:



(-0.361655, -0.657913, -0.900599)
(-0.72331, 0.684174, 0.198802)
(0.915035, 0.0262616, -0.701797)
(0.55338, -0.631651, 0.397604)
(0.191725, 0.710436, -0.502995),...









share|cite|improve this question











$endgroup$












  • $begingroup$
    Please try to make the titles of your questions more informative. For example, Why does $a<b$ imply $a+c<b+c$? is much more useful for other users than A question about inequality. From How can I ask a good question?: Make your title as descriptive as possible. In many cases one can actually phrase the title as the question, at least in such a way so as to be comprehensible to an expert reader. You can find more tips for choosing a good title here.
    $endgroup$
    – Shaun
    Dec 8 '18 at 11:56














0












0








0





$begingroup$


I want to used R-sequence proposed by Martin Roberts to generate points in range [-1,1].
In this post, Martin Roberts mentioned that:




... to convert to a range of [-1,1], simply apply the linear
transformation x:=2x+1. The result is



(-0.361655, -0.657913, -0.900599)



(-0.72331, 0.684174, 0.198802)



(0.915035, 0.0262616, -0.701797)



(0.55338, -0.631651, 0.397604)



(0.191725, 0.710436, -0.502995),...




I am not specialist in math, I just want to know how to apply this transformation to generate points in range [-1,1]?
and in which part of the provided code?



This code generates points in range [0,1]



# Use Newton-Rhapson-Method
def gamma(d):
x=1.0000
for i in range(20):
x = x-(pow(x,d+1)-x-1)/((d+1)*pow(x,d)-1)
return x

d=3
n=5

g = gamma(d)
alpha = np.zeros(d)
for j in range(d):
alpha[j] = pow(1/g,j+1) %1
z = np.zeros((n, d))
for i in range(n):
z = (0.5 + alpha*(i+1)) %1

print(z)


The result is:



(0.319173, 0.171044, 0.0497005)
(0.138345, 0.842087, 0.599401)
(0.957518, 0.513131, 0.149101)
(0.77669, 0.184174, 0.698802)
(0.595863, 0.855218, 0.248502) ...


How to apply this linear transformation x:=2x+1 to get this result:



(-0.361655, -0.657913, -0.900599)
(-0.72331, 0.684174, 0.198802)
(0.915035, 0.0262616, -0.701797)
(0.55338, -0.631651, 0.397604)
(0.191725, 0.710436, -0.502995),...









share|cite|improve this question











$endgroup$




I want to used R-sequence proposed by Martin Roberts to generate points in range [-1,1].
In this post, Martin Roberts mentioned that:




... to convert to a range of [-1,1], simply apply the linear
transformation x:=2x+1. The result is



(-0.361655, -0.657913, -0.900599)



(-0.72331, 0.684174, 0.198802)



(0.915035, 0.0262616, -0.701797)



(0.55338, -0.631651, 0.397604)



(0.191725, 0.710436, -0.502995),...




I am not specialist in math, I just want to know how to apply this transformation to generate points in range [-1,1]?
and in which part of the provided code?



This code generates points in range [0,1]



# Use Newton-Rhapson-Method
def gamma(d):
x=1.0000
for i in range(20):
x = x-(pow(x,d+1)-x-1)/((d+1)*pow(x,d)-1)
return x

d=3
n=5

g = gamma(d)
alpha = np.zeros(d)
for j in range(d):
alpha[j] = pow(1/g,j+1) %1
z = np.zeros((n, d))
for i in range(n):
z = (0.5 + alpha*(i+1)) %1

print(z)


The result is:



(0.319173, 0.171044, 0.0497005)
(0.138345, 0.842087, 0.599401)
(0.957518, 0.513131, 0.149101)
(0.77669, 0.184174, 0.698802)
(0.595863, 0.855218, 0.248502) ...


How to apply this linear transformation x:=2x+1 to get this result:



(-0.361655, -0.657913, -0.900599)
(-0.72331, 0.684174, 0.198802)
(0.915035, 0.0262616, -0.701797)
(0.55338, -0.631651, 0.397604)
(0.191725, 0.710436, -0.502995),...






linear-transformations python






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share|cite|improve this question













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edited Dec 8 '18 at 15:20









Key Flex

8,58761233




8,58761233










asked Dec 8 '18 at 11:48









user10608907user10608907

32




32












  • $begingroup$
    Please try to make the titles of your questions more informative. For example, Why does $a<b$ imply $a+c<b+c$? is much more useful for other users than A question about inequality. From How can I ask a good question?: Make your title as descriptive as possible. In many cases one can actually phrase the title as the question, at least in such a way so as to be comprehensible to an expert reader. You can find more tips for choosing a good title here.
    $endgroup$
    – Shaun
    Dec 8 '18 at 11:56


















  • $begingroup$
    Please try to make the titles of your questions more informative. For example, Why does $a<b$ imply $a+c<b+c$? is much more useful for other users than A question about inequality. From How can I ask a good question?: Make your title as descriptive as possible. In many cases one can actually phrase the title as the question, at least in such a way so as to be comprehensible to an expert reader. You can find more tips for choosing a good title here.
    $endgroup$
    – Shaun
    Dec 8 '18 at 11:56
















$begingroup$
Please try to make the titles of your questions more informative. For example, Why does $a<b$ imply $a+c<b+c$? is much more useful for other users than A question about inequality. From How can I ask a good question?: Make your title as descriptive as possible. In many cases one can actually phrase the title as the question, at least in such a way so as to be comprehensible to an expert reader. You can find more tips for choosing a good title here.
$endgroup$
– Shaun
Dec 8 '18 at 11:56




$begingroup$
Please try to make the titles of your questions more informative. For example, Why does $a<b$ imply $a+c<b+c$? is much more useful for other users than A question about inequality. From How can I ask a good question?: Make your title as descriptive as possible. In many cases one can actually phrase the title as the question, at least in such a way so as to be comprehensible to an expert reader. You can find more tips for choosing a good title here.
$endgroup$
– Shaun
Dec 8 '18 at 11:56










1 Answer
1






active

oldest

votes


















0












$begingroup$

The linear transformation seems to be false. You need



$f: begin{cases}
[0, 1] &to [-1, 1] \
x &mapsto 2x mathop{mathbf{-}} 1
end{cases}$



Simply apply the linear transformation (a function!) to every element in the vector. Since I have no python installed, the following source code to do this is not tested:



# ...
for i in range(n):
for j in range(d):
z[i][j] = 2 * z[i][j] - 1
print(z)


EDIT: Another method would use list comprehension, something like [[2 * z[i][j] - 1 for j in range(d)] for i in range(n)] (again untested). But Python does not operate on matrices implicitly like Mathematica and Octave do.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    it is working. Would you please give examples for another methods for transformation? Thank you
    $endgroup$
    – user10608907
    Dec 8 '18 at 12:45











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









0












$begingroup$

The linear transformation seems to be false. You need



$f: begin{cases}
[0, 1] &to [-1, 1] \
x &mapsto 2x mathop{mathbf{-}} 1
end{cases}$



Simply apply the linear transformation (a function!) to every element in the vector. Since I have no python installed, the following source code to do this is not tested:



# ...
for i in range(n):
for j in range(d):
z[i][j] = 2 * z[i][j] - 1
print(z)


EDIT: Another method would use list comprehension, something like [[2 * z[i][j] - 1 for j in range(d)] for i in range(n)] (again untested). But Python does not operate on matrices implicitly like Mathematica and Octave do.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    it is working. Would you please give examples for another methods for transformation? Thank you
    $endgroup$
    – user10608907
    Dec 8 '18 at 12:45
















0












$begingroup$

The linear transformation seems to be false. You need



$f: begin{cases}
[0, 1] &to [-1, 1] \
x &mapsto 2x mathop{mathbf{-}} 1
end{cases}$



Simply apply the linear transformation (a function!) to every element in the vector. Since I have no python installed, the following source code to do this is not tested:



# ...
for i in range(n):
for j in range(d):
z[i][j] = 2 * z[i][j] - 1
print(z)


EDIT: Another method would use list comprehension, something like [[2 * z[i][j] - 1 for j in range(d)] for i in range(n)] (again untested). But Python does not operate on matrices implicitly like Mathematica and Octave do.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    it is working. Would you please give examples for another methods for transformation? Thank you
    $endgroup$
    – user10608907
    Dec 8 '18 at 12:45














0












0








0





$begingroup$

The linear transformation seems to be false. You need



$f: begin{cases}
[0, 1] &to [-1, 1] \
x &mapsto 2x mathop{mathbf{-}} 1
end{cases}$



Simply apply the linear transformation (a function!) to every element in the vector. Since I have no python installed, the following source code to do this is not tested:



# ...
for i in range(n):
for j in range(d):
z[i][j] = 2 * z[i][j] - 1
print(z)


EDIT: Another method would use list comprehension, something like [[2 * z[i][j] - 1 for j in range(d)] for i in range(n)] (again untested). But Python does not operate on matrices implicitly like Mathematica and Octave do.






share|cite|improve this answer











$endgroup$



The linear transformation seems to be false. You need



$f: begin{cases}
[0, 1] &to [-1, 1] \
x &mapsto 2x mathop{mathbf{-}} 1
end{cases}$



Simply apply the linear transformation (a function!) to every element in the vector. Since I have no python installed, the following source code to do this is not tested:



# ...
for i in range(n):
for j in range(d):
z[i][j] = 2 * z[i][j] - 1
print(z)


EDIT: Another method would use list comprehension, something like [[2 * z[i][j] - 1 for j in range(d)] for i in range(n)] (again untested). But Python does not operate on matrices implicitly like Mathematica and Octave do.







share|cite|improve this answer














share|cite|improve this answer



share|cite|improve this answer








edited Dec 8 '18 at 15:16

























answered Dec 8 '18 at 12:13









user7427029user7427029

1207




1207












  • $begingroup$
    it is working. Would you please give examples for another methods for transformation? Thank you
    $endgroup$
    – user10608907
    Dec 8 '18 at 12:45


















  • $begingroup$
    it is working. Would you please give examples for another methods for transformation? Thank you
    $endgroup$
    – user10608907
    Dec 8 '18 at 12:45
















$begingroup$
it is working. Would you please give examples for another methods for transformation? Thank you
$endgroup$
– user10608907
Dec 8 '18 at 12:45




$begingroup$
it is working. Would you please give examples for another methods for transformation? Thank you
$endgroup$
– user10608907
Dec 8 '18 at 12:45


















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