performance - Speeding up an Euler numerical scheme in python -


let's have update scheme looks this:

import numpy np  n = 1000 dt = 0.01  x = np.zeros(n) x[0] = 0.5  in xrange(1, n):      rand = np.random.normal(loc=0.,scale=1.)      x[i] = x[i-1]*(1 + dt + np.sqrt(dt)*rand)

what best strategy speeding code of form, current array element needs previous array element make calculation?

i attempting put vectorised form i'm bit stuck how use trailing array element update current one.

if there better solutions don't involve vectorisation i'm open too.

try this:

x = np.random.randn(1000) x += 1 x[0] = 0.5 y = np.cumprod(x)

answer in y


Comments

Post a Comment

Popular posts from this blog

java - WARN : org.springframework.web.servlet.PageNotFound - No mapping found for HTTP request with URI [/board/] in DispatcherServlet with name 'appServlet' -

this question has answer here: why spring mvc respond 404 , report “no mapping found http request uri […] in dispatcherservlet”? 3 answers i trying making simple bbs i'm encountering following error, warn : org.springframework.web.servlet.pagenotfound - no mapping found http request uri [/board/] in dispatcherservlet name 'appservlet' i have tried solve error many times, have failed. how can solve error? here web.xml, controllerand , servlet-context. my web.xml <?xml version="1.0" encoding="utf-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" xsi:schemalocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <filter> <filter-nam...
Read more

1111. appearing after print sequence - php -

morning, i have code takes string of shoe sizes, explodes , puts in table. code works , info displayed correctly on page after table there few 1's after table. i'm confused this. so table looks (in columns of 3 on webpage) available in following sizes: 3 4 5 6 9 10 111 here's codes, purpose of example $x = 3|4|6|10|9 function get_sizes_pipe($x) { $counter = 0; $splits = explode("|",$x); asort($splits); $x = print "<table class='greentable'>"; $x .= print "<thead><tr><th scope='col' colspan='3' abbr='starter'>available in following sizes:</th></tr></thead><tbody><tr>"; foreach ($splits $split) { $entry = print "<td>".$split."</td>"; if($counter == 2){ $entry .= print "</tr><tr>"; $counter =0; } else { $counter++; ...
Read more

android - How to create dynamically Fragment pager adapter -

i unable create dynamic layout each tabs, able create tabs dynamically constructor(public mypageradapter(fragmentmanager fm , int nooftabs)), coudn't inflate view each tabs creating each fragment should dyanmic. public class mypageradapter extends fragmentpageradapter { private final string[] titles = { "categories", "home", "top paid", "top free", "top grossing", "top new paid", "top new free", "trending" }; int nooftabs; **public mypageradapter(fragmentmanager fm , int nooftabs) { super(fm); this.nooftabs = nooftabs; }** /*public mypageradapter(fragmentmanager fm) { super(fm); }*/ @override public charsequence getpagetitle(int position) { return titles[position]; } @override public int getcount() { ...
Read more