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Questions tagged [sym]

12 questions
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Identify powers in an algebraic expression for a Buckingham Pi calculation in MatLab

This is a continuation of an earlier question I asked here. If I create a symbolic expression in MatLab syms L M T F = M*L/T^2 I want to identify the powers of each dimension M, L, or T. In this case, the answer should be for M, 1 for L, 1 for T,…
WnGatRC456
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Calculating CAGR with differing time-based data. Issue with variable column referencing in R

I have a table of Calpers Private Equity Fund performance from several years. I cleaned and joined all the data into a large table with 186 entries for individual fund investments. Some of these funds have data for 5 yrs, most for 4 or less. I…
xtufer
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How to perform a loop with sym() in r?

I have a data frame with several continuous variables. I need to generate the logarithm of each continuous variable. The names of each new variables must be made up of the original variable name adding _ln. I would like to generate a loop to do this…
DavidMB
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Error in `sym()`: using wbm() function from the package 'panelr'

I have a panel dataset with 289 local governments and 3 years. One of my explanatory variables, 'manco', is a time-invariant variable, so I'm forced to use an alternative method to fixed effects, in this case i chose the within-between model, also…
mrf6345
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Crash Running in Matlab Simulink on Mac M1MAX

I get the following error trying to run Matlab code using parallel toolbox with Simulink. XXX.m is a ficticious name. This is error i get, anyone know how to solve it. Error using XXX.m Cannot load model 'XXX.m' on parallel workers. If this is a…
George Cisneros
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I cannot get the meta of a kdb+ table - sym error

I have a table that I want to find the meta for but I keep getting the following error. I also have similar tables with the same issue and I don't have a sym file. The Trade table for example has the sym column present already so I'm unsure why the…
K grass
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symbolic variables and vpasolve (MATLAB) for dynamic input

I want to find the corresponding outputs for symbolic variables (Tg Tc Tab Tto Tti Tfo) for a dynamic set of inputs (G_in, Vw, Ta). Kindly seeking for probable solutions. Thanks! (I will attach the code on request since I cant upload it)
Jacob E
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Evaluate symfun at a symbolic variable instead of a number in MATLAB

I created a symbolic function in MATLAB R2021b using this script with the goal of solving an ODE. syms phi(x) lambda L eqn_x = diff(phi,x,2) == -lambda*phi; dphi = diff(phi,x); cond = [phi(0)==0, dphi(1)==0]; % this is the line where the problem…
WnGatRC456
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Count number of unique symbols for a Buckingham Pi calculation in an expression with MATLAB

I am trying to write a script that goes through the Buckingham Pi theorem given a list of variables, each having a dimension. The set of dimensions do not need to be unique (it can contain repeats) only the same size as the set of variables. clc,…
WnGatRC456
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When i try to multiply function with symbolic variables I get an error

When I use the integral command I get the following error, even though I defined all of the variables: Error using integralCalc/finalInputChecks Input function must return 'double' or 'single' values. Found 'sym'. Error in…
Amitai
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Is there a way to derive implict ODE function from big symbolic expression?

I'm Davide and I have a problem with the derivation of a function that later should be given to ode15i in Matlab. Basically I've derived a big symbolic expression that describe the motion of a spececraft with a flexible appendice (like a solar…
FluidBat
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sym not working with vector has more than 1 element

df <- data.frame(A = c(1,1,1), B = c(2,2,3)) variables <- c("A", "B") dplyr::count(df, !!!rlang::sym(variables)) Error: Only strings can be converted to symbols Run `rlang::last_error()` to see where the error occurred. It works if variables is…
Bear Bile Farming is Torture
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