## Summation index must be a symbolic variable

The index of summation, here the letter i, is a dummy variable whose value will To expand this summation notation, that is, to determine the set of addends that  The result of symbolic operations typically have this type. If the shape is a Variable argument, then you might need to use the optional ndim Construct an array from an index array and a set of arrays to choose from. theano.tensor. sum (x, axis=None, dtype=None, keepdims=False, acc_dtype=None)[source]¶

In mathematics, summation is the addition of a sequence of any kind of numbers, called where i represents the index of summation; ai is an indexed variable Thus, given such a function f, the problem is to compute the antidifference of f,  symbolic variable. Summation index, specified as a symbolic variable. If you do not specify this variable,  The sum function sums the input over a dimension, while the symsum function sums the input over an index. Consider the definite sum S = ∑ k = 1  Array indices must be positive integers or logical values. According to the documentation of symsum , the variable for range ( i in your case should be a symbolic variable). You haven't defined i as a symbolic variable and hence it is considered to To do your intended operation, I would use sum like this: The sym command lets you construct symbolic variables and expressions. For example Note To create a symbolic expression that is a constant, you must use the double-precision floating point number to a sum of two binary numbers, in the now be manipulated by field and index to access a particular portion of the.

## Error:index must be a positive integer or logical.. Learn more about index must be a positive integer or logical.

The problem is final graph of 'summ' should be equal or less than amplitude of ' deltaHvec'. But I am getting Because the index variable is same for both the summations. The symbolic tool box can be used for single summation. I tried to   The purpose of this document is to explain the features of MATLAB that are useful for applying the techniques Summation index must be a symbolic variable. Symbolic variables are treated differently than regular variables in Matlab and must be created using the sym() or syms() functions. syms A B lambda X Y The end index can be inf, in which case an infinite sum is performed. symsum(2^(-X), 0  When defining a function, ensure that the arguments are symbolic variables and the body of the function is a SYM expression. When indexing, the input must be

### If the first argument is a string, the independent variable must be x. symsum: Evaluates a symbolic sum in closed form. syms x n; symsum(x^n/n, Index, 261

The variable of summation is represented by an index which is placed beneath the summation sign. The index is often represented by i. (Other common possibilities for representation of the index are j and t.) The index appears as the expression i = 1. The index assumes values starting with the value on the right hand side of the equation and ending with the value above the summation sign. The summation operator is used to indicate that a set of values should be added together. The formulas used to compute moments for a probability distribution are based on the summation operator. This is because each calculation must be repeated for each possible value of a random variable and the results must be summed. In mathematics, summation is the addition of a sequence of any kind of numbers, called addends or summands; the result is their sum or total. Besides numbers, other types of values can be summed as well: functions, vectors, matrices, polynomials and, in general, elements of any types of mathematical objects on which It successfully sums the field for numeric data, however when I run the application and want to sum company code, which is the first item in my drop down, it gives me the following error; A variable index must be a real positive integer. The summation convention requires that one must never allow a summation index to appear more than twice in any given expression. Because of this rule it is sometimes necessary to replace one dummy summation symbol by some other dummy symbol in order to avoid having three or more indices occurring on the same side of the equation. The index notation is a very powerful notation and can be used to concisely represent many complex equations.

### Symbolic summation is a vast research area in computer algebra. such a G, then a plausible approach is to apply an algorithm which solves the additive the summand T is a function of the summation index k and of a parameter n, i.e., T=T(n,k). The exported variables indicate the functions that are accessible to users.

— In ∑ a it should be obvious that a itself is not a summable expression, so it's clear and unambiguous that the subscript must be provided from the sum. Whereas ai is an evaluated expression that could indeed be taken as a constant to sum some over with some other index variable. – leftaroundabout Mar 27 '12 at 22:36. I think that Matlab's symbolic core uses Maple's implementation or something like that. If you can do something in Maple, then you should be able to do that in symbolic Matlab. Unfortunately, I do not know much of Maple or Mathematica. – jespestana Oct 15 '12 at 13:10 In general, you can use sym or syms to create symbolic variables. We recommend you use syms because it requires less typing. Note To create a symbolic expression that is a constant, you must use the sym command. For example, to create the expression whose value is 5, enter f = sym('5'). Note that the command f = 5 does not define f as a symbolic The variable of summation is represented by an index which is placed beneath the summation sign. The index is often represented by i. (Other common possibilities for representation of the index are j and t.) The index appears as the expression i = 1. The index assumes values starting with the value on the right hand side of the equation and ending with the value above the summation sign.

## In mathematics, summation is the addition of a sequence of any kind of numbers, called addends or summands; the result is their sum or total. Besides numbers, other types of values can be summed as well: functions, vectors, matrices, polynomials and, in general, elements of any types of mathematical objects on which

GAMS uses the traditional symbols for addition (+) , subtraction (-) The extension to two or more controlling indices should be obvious. It is also possible to sum simultaneously over the domain of two or more sets as in the first In the context of equation definitions, scalars, parameters and variables may appear freely in  Symbolic Math Toolbox™ provides two functions for calculating sums: sum finds the sum of elements of symbolic vectors and matrices. Unlike the MATLAB ® sum, the symbolic sum function does not work on multidimensional arrays. For details, follow the MATLAB sum page. symsum finds the sum of a symbolic series. If you do not specify k, symsum uses the variable determined by symvar as the summation index. If f is a constant, then the default variable is x. symsum(f,k,[a b]) or symsum(f,k,[a; b]) is equivalent to symsum(f,k,a,b). In mathematics, summation is the addition of a sequence of any kind of numbers, called addends or summands; the result is their sum or total. Besides numbers, other types of values can be summed as well: functions, vectors, matrices, polynomials and, in general, elements of any types of mathematical objects on which In using the summation symbol, take note of the following: An index variable is just a “dummy” variable. It means that you can use a different index variable without changing the value of the sum. The sum is the same as and is the same as. Here, the dummy variable is , the lower limit of summation is 1, and the upper limit is 5. Example. Sometimes, you will see summation signs with no dummy variable specified, e.g., ∑ = In such cases the correct dummy variable should be clear from the context. I want to write an (somehow) enhanced sum function which takes a number of indices at once, but I cannot understand how to get it work. Here is what I currently have:

In using the summation symbol, take note of the following: An index variable is just a “dummy” variable. It means that you can use a different index variable without changing the value of the sum. The sum is the same as and is the same as. Here, the dummy variable is , the lower limit of summation is 1, and the upper limit is 5. Example. Sometimes, you will see summation signs with no dummy variable specified, e.g., ∑ = In such cases the correct dummy variable should be clear from the context. I want to write an (somehow) enhanced sum function which takes a number of indices at once, but I cannot understand how to get it work. Here is what I currently have: