Community Profile # jacob Mitch

30 total contributions since 2019

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Question

Plotting missing data in different colour
Im trying to plot prices as dots and my guess price nan values as different coloured dots. If I have. years=[1;2;3;4;5;6;7;8;...

1 hour ago | 0 answers | 0

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Question

Boundary conditions Partial differential equations
I'm trying to set boundary conditions according to https://uk.mathworks.com/help/matlab/ref/pdepe.html I have boundary conditio...

1 day ago | 0 answers | 0

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Question

Simulating Stochastic Differential equations
I am just learning about Stochastic differential equations if I have a SDE of dX(t) = -μ*X(t)*dt + σ*W(t) X0=x0>0 where W(t) i...

2 days ago | 0 answers | 0

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Question

Detecting change in sign of values of a column
If I a data file with 3 columns the first being the x cordinates second being the y cordinates and the third being the z. Data(...

4 days ago | 1 answer | 0

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Using Runge Kutta function to solve Rossler equations
I have created a runge kutta 4th order function by so

4 days ago | 1 answer | 0

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Question

Getting rid of data that does not meet conditions: Poincare section
If I have a data array where the first row corresponds to the x axis second to the y axis and third row to the z axis. I want t...

5 days ago | 1 answer | 0

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Question

Deleting columns corresponding to time value
If I have a time axis of t=[0:1:4]; %time step 1 that corresponds to x,y,z data as an array where the first row is x second ...

5 days ago | 2 answers | 0

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Question

how to call functions properly: Index in position 1 is invalid. Array indices must be positive integers or logical values.
I'm trying to work with multiple functions but I keep getting this error, its for the runge kutta method solving rossler equatio...

7 days ago | 1 answer | 0

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Question

Using ODE45 to solve Rossler equations
The Rossler equations are defined as x'(t)=-x(t)-y(t) y'(t)=ax(t)+y(t) z'(t)=b+z(t)(x(t)-c) and I am trying to use ode45 to...

8 days ago | 1 answer | 0

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Question

Data: Interp1 spline and cubic method
Im just trying to figure out how I would use the Interp1 function with the spline method and the Interp1 withe cubic method for...

15 days ago | 1 answer | 0

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Question

Summing data columns in a series
If I have a 2 data columns and I want to raise them to the power of K and sum the using sigma notation from k=1 to 10 how would...

16 days ago | 1 answer | 0

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Question

Adding new column of data from loop
Say I have a loop running how would I create a new variable that holds the columns I want say. for .... v= %some code ...

16 days ago | 2 answers | 0

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Question

Using Polyfiti, Polyval, and plotting
say I have a data file with the first column being days and the second being prices. How would I go about creating an approximat...

16 days ago | 1 answer | 0

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Question

Summation of vectors: use of sum function in loop
Say I have a a series %%(1/t)\sqrt{\sum_{k=1}^{s}(vector^t+vectortwo^t)^2}%% or (1/t)*sqrt of (sigma from t=1 to s) (vector^t+v...

19 days ago | 1 answer | 0

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Question

Have I used polyfit/polyval correctly
I am just trying to get used to the polyfit and polyval function. My question says to use the polyfit and polyval functions to...

19 days ago | 0 answers | 0

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Question

Getting rid of built in vectorised function (Max)
I just wanted to see if its possible to get rid of max in the following whilst still producing the same result. A=[1,2,3,4,5,6...

28 days ago | 0 answers | 0

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Question

Getting rid of a for loop
If I have my code as function [value1, value2] = scope(input) c=1; x=length(input); for z=2:x if z...

28 days ago | 3 answers | 0

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Question

Calculating ∆t from data set and plotting
If I have financial data with prices as the first column and I create an array of integers from 1 to the length of data to use a...

1 month ago | 0 answers | 0

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Question

Plotting prices as a function of time
Im trying to understand data from a data file. If I have d∆t(t) = x(t + ∆t) − x(t) , where ∆t is the trading days difference ...

1 month ago | 0 answers | 0

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Question

Plotting data as a function of time
I'm just trying to understand plotting prices as a function of time, if I have price data of prices in a column, say x=[1;2;3;4;...

1 month ago | 1 answer | 0

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Question

Use fprintf for data from a table
if I have data from a mat file say 3 7 2005 30 %1st 3 columns are day month year print loss 1 4 2005 35 1 5 2005 24 2 6 20...

1 month ago | 1 answer | 0

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Question

converting Matlab plot example
The matlab example page provides which plots 1 value for the maxima and minima on a line graph I am trying to convert it but thi...

1 month ago | 1 answer | 0

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Question

How to plot points on a line
Say I have a random sequence of such as new=randn(5,1) which produces y values of ans = -0.9118 0.0494 1.0780 ...

1 month ago | 1 answer | 0

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Question

Changing a for loop to recursion
Just wondering if I could get a bit of help on this. How would I change this code to remove the for loop so it operates recursiv...

1 month ago | 1 answer | 0

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Question

How to add values from if statements to a column
say I have function [x,y]=valuesof(data) input= data; t=length(data); for z=2:t if input(z-1)>input(z) && input (z)<...

1 month ago | 1 answer | 0

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Question

Plotting infinite series on interval
I have the following function for error approximation function y = Approx(x,N); Approx=zeros(1,length(x)); for n=0:N Ap...

1 month ago | 0 answers | 0

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Question

Series expansion: looping over different inputs
Say I have the approximation My question asks that I create two functions to calculate this approximation for an interval of x-...

1 month ago | 1 answer | 0

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Question

Error approximation as a function
I have this error approximation and I am trying to create two functions. One which loops over the values and the second which...

1 month ago | 0 answers | 0

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Question

using a function to answer new questions
I have created function y=Gss(n); a=3; b=0.2; N(1)=0.2; for v=2:n+1 N(v)=exp(-a*N(v-1)^2)+b; end y=N(v);...

2 months ago | 1 answer | 0