py_RC Elastic update

Posted on 08/06/2024 by dougaj4

Following the previous post I have updated the py_RC Elastic spreadsheet and code to work with the new solver function, and also add new functionality. The updated files can be downloaded from:

py_RC Elastic.zip

For details of the pyxll app required to conect the Python code to Excel see Python and pyxll.

As reported in the previous post, the py_CurveatMA function returns the curvature of a reinforced concrete section for a specified axial force and bending moment, with non-linear steel and concrete properties (in spite of the spreadsheet name!):

The py_CurveatMA function calls the functions py_SectForceMV, Stressatx and py_EC2ForceM, which can also be called directly from the spreadsheet:

New functions will calculate the development of shrinkage and creep over time, according to the AS 3600, AS 5100.5, Eurocode 2, or fib model code provisions:

Also “basic drying shrinkage” (to AS 3600) can be calculated from test results:

Finally the EC2Props function returns 13 concrete properties defined in Eurocode 2, for a specified compressive strength:

The other functions available with this spreadsheet are described at: SLS Concrete design with Python

Posted in Concrete, Excel, Link to Python, Newton, NumPy and SciPy, PyXLL, UDFs | Tagged , , , , , , | Leave a comment

Scipy solver update

Posted on 31/05/2024 by dougaj4

The py_SolveFS function calls the Scipy optimize.root function to solve multi-variable equations. Examples are found on the py_Solvers spreadsheet, see Scipy Functions with Excel and pyxll 4 – Solvers 2.

One problem with using this function is that the input data must be arranged to suit the Scipy root function, as shown on the help screen below:

The root function requires an initial guess for each of the unknown values (x0). Any additional known variables are passed in the args parameter, which is a tuple, that is a list or list of lists. If py_SolveFS is called from an interface function, that function can arrange the input in the required format, but if it is called directly from the spreadsheet, and there are many input values, it is convenient if the data can be arranged in a range, with each column being treated as a 1D array, that will be converted to a Python list.

To allow this to be used in a flexible way I have added an optional TransposeVals argument to the py_SolveFS function, with a default value of True. If input arrays are arranged row-wise on the spreadsheet this should be set to False.

The revised inputs for the function are:

If TransposeVals is omitted or set to False the Values data must be arranged in columns, either as a single column:

Or as a range with two or more columns:

In the example above the py_SolveFS function is called both indirectly with py_CurveatMA, and directly. For the indirect case the Values data is in Columns C and F. For the direct case the data has been copied to adjacent columns (J and K). In both cases the target values are passed as a single column array, which is combined with the Values data in py_SolveFS.

The new version of py_SolveFS is included in the Scipy download file at:

py_Scipy.zip

For information on the pyxll package, required to connect the Python code to Excel, see: https://newtonexcelbach.com/python-and-pyxll/.

Posted in Excel, Link to Python, NumPy and SciPy, PyXLL, UDFs | Tagged , , , , , , , | Leave a comment

Regular Expressions in Excel

Posted on 25/05/2024 by dougaj4

I recently discovered that Microsoft are working on Excel functions to work with Regular Expressions. A beta version is currently available to those on the “insider” program, but this functionality has long been available through VBA, and can also be accessed from Python, using pyxll.

Details of the new Excel functions are at:

https://insider.microsoft365.com/en-us/blog/new-regular-expression-regex-functions-in-excel

I have previously covered the VBA use of regular expressions in detail at:

https://newtonexcelbach.com/2014/11/30/extracting-numbers-from-text-and-regular-expressions/
https://newtonexcelbach.com/2014/12/08/more-on-regular-expressions/
https://newtonexcelbach.com/2017/03/11/extracting-numbers-from-text-update/

Detailed documentation of the Python code for regular expressions is at:

Excel Regex Tutorial (Regular Expressions)

From the Analyst Cave tutorial I was able to very quickly write four Excel user defined functions using pyxll to access the Python code:

import re

@xl_func()
@xl_arg('regexp', 'str')
@xl_arg('txt', 'str')
def RESearch(regexp, txt, rtn = 3):
    """
Returns a Match object if there is a match for regexp anywhere in txt

:param regexp: Regular expression
:param txt: Text to be searched
:param rtn: Value to be returned; 1 = span array for match location, 2 = input txt, 3 = list of matches (default)
    """
    x = re.search(regexp, txt)
    try:
        # span() string group()
        if rtn == 1:
            return x.span()
        elif rtn == 2:
            return x.string
        else:
            return x.group()
    except:
        return "No match"

@xl_func()
@xl_arg('regexp', 'str')
@xl_arg('txt', 'str')
def REFindall(regexp, txt):
    """
Returns a list containing all matches 

:param regexp: Regular expression
:param txt: Text to be searched
    """
    x = re.findall(regexp, txt)
    try:
        return x
    except:
        return "No match"

@xl_func()
@xl_arg('regexp', 'str')
@xl_arg('txt', 'str')
def RESplit(regexp, txt):
    """
Returns a list where the string has been split at all matches 

:param regexp: Regular expression
:param txt: Text to be searched
    """
    x = re.split(regexp, txt)
    try:
        return x
    except:
        return "No match"

@xl_func()
@xl_arg('regexp', 'str')
@xl_arg('replace', 'str')
@xl_arg('txt', 'str')
def RESub(regexp, replace, txt):
    """
Replaces one or many matches with a string 

:param regexp: Regular expression
:param txt: Text to be searched
    """
    x = re.sub(regexp, replace, txt)
    try:
        return x
    except:
        return "No match"

Example results are shown below, using an example from the Microsoft site:

Posted in Excel, Link to Python, PyXLL, UDFs, VBA | Tagged , , , , , , | Leave a comment

Pale Blue Dot

Posted on 24/05/2024 by dougaj4

34 years ago Carl Sagan presented an image of the Earth taken from outer space, known as the pale blue dot.

An event very different from a 13 year old boy singing a song he had written himself, but the message was the same:

Posted in Climate, Newton | Tagged , | Leave a comment

Rory Phillips – The Truth

Posted on 13/05/2024 by dougaj4

“‘The Truth’ is a passionate call to action on climate change from 13 year old Rory Phillips. “I wanted to say something with this song. The lyrics are subtle, not in your face; but the message is clear. We need to do more, from the top down.”

Posted in Bach, Climate, Newton | Tagged , , | Leave a comment