Question

Out of Memory Error when Copying
Hello, I have a function which symbolically solves for a set of differential equations and writes them out to a text file. B...

nästan 12 år ago | 0 answers | 0

Question

Simplify Symbolic Values of All Fields in Struct
Hello, I have a struct containing multiple fields. The value of each field is a symbolic expression. Is there a way I can s...

nästan 12 år ago | 1 answer | 0

Answered
Using a Symbolic Expression
For the expressions that exceed the maximum command line length, I was able to print them to a file instead of the command line ...

nästan 12 år ago | 0

| accepted

Question

MATLAB solve function is taking a very long time
Hello, I have a system of 17 equations and 23 unknowns and I'm using the MATLAB "solve" function to solve symbolically for 17...

nästan 12 år ago | 2 answers | 0

Question

Using a Symbolic Expression
Hello, I have one function that creates a symbolic expression for a variable, which is often lengthy. In another function, I...

nästan 12 år ago | 2 answers | 0

Answered
Help with the getfield command?
Oh, I need to use getfield(S,MyFieldNames{1});

nästan 12 år ago | 0

| accepted

Question

Help with the getfield command?
Hello, I have a struct S and I'm trying to access the values of each field without having to hard code in the field names. ...

nästan 12 år ago | 1 answer | 0

Question

In a symbolic expression, how can I extract all terms that have a common specific variable?
Hello, In a symbolic expression, is there a way to extract all terms that have a common specific variables? For example, if ...

nästan 12 år ago | 1 answer | 0

Question

Deleting rows and columns of all zeroes in a symbolic matrix
Hello, How can I delete all rows and columns of all zeroes in a symbolic matrix? The solution listed here ( http://www.mat...

nästan 12 år ago | 2 answers | 0

Answered
In a struct, how can you extract values for a vector of fieldnames
MyFieldNames = fieldnames(MyStruct); for i=1:3 MyValues(i,1) = getfield(MyStruct,MyFieldNames{i}); end

nästan 12 år ago | 2

| accepted

Question

In a struct, how can you extract values for a vector of fieldnames
Hello, I have a struct called MyStruct. I can extract the field names with the command MyFieldNames = fieldnames(MyStruct...

nästan 12 år ago | 5 answers | 1

Question

Finding all possible row combinations of a matrix that add to zero
Hello, I'm looking for a general way to find all possible row combinations of a matrix that add to zero. For instance, for...

nästan 12 år ago | 5 answers | 0

Question

Creating an empty sym variable?
Hello, How I can create an empty 0x0 sym variable? Such as x=[] x={}, expect I want to make x an empyt sym, not an empty dou...

ungefär 12 år ago | 1 answer | 0

Question

Solving a System of Equations with syms
Hello, I have a system of 10 equations and 14 unknowns. I want to solve this system of equations for 6 particular unknowns i...

ungefär 12 år ago | 1 answer | 0

Question

Question about Symbolic Differentiation
Hello, If I write the following code: syms x t answer = diff(x,t) then answer = 0. Is it possible to declare ...

ungefär 12 år ago | 1 answer | 0

Answered
Solving a coupled set of differential equations in MATLAB?
I was not able to find an easy way to do this. I had to define a new variable and use substitution in order to solve. So ori...

ungefär 13 år ago | 0

| accepted

Question

Mixture of Algebraic and Differential Equations
Hello, For example, is there a way to solve a system of 10 unknowns, 8 differential equations, and 2 algebraic equations in M...

mer än 13 år ago | 0 answers | 0

Question

Solving a coupled set of differential equations in MATLAB?
Hello, I have a set of coupled differential equations Ax + B dx/dt + C dy/dt = D Ey + F dy/dt + G dx/dt = H The problem ...

mer än 13 år ago | 2 answers | 0

Question

ode45
Hello, When using ode45, I know I can specify the integrand as a function of time. For instance, dx/dt = cos(t) - x. Is...

mer än 13 år ago | 1 answer | 0

Question

Numerically Integrating an Array
I have often integrated a function by using quad and dblquad. When using quad and dblquad, I can increase the tolerance paramet...

nästan 14 år ago | 2 answers | 0