Getting the dimension of a Vector in Math.NET - vector

If I was given a Vector in Math.NET, how can I check the number of dimensions that it has? I can't seem to find anything in the documentation

You're looking for the Count property.
If I remember correctly, the property was named Count instead of Length or Dimensions to be consistent with RowCount and ColumnCount in matrices.

Related

Align Text To Row Identified by Number and to ID Matching that Embedded in String

I need to align text in an ALERT STRING column with the row identified by number in an ID ROW column.
Additionally, I need to also align the same ALERT STRING text with the same ID ROW number AND with the ID matching that embedded in a string in the TEXT WITH ID column. (This double-check will sometimes be necessary with the real-world data.)
So far, I've only figured out how to align the ALERT STRING with the ID matching that embedded in the TEXT WITH ID column:
=LOOKUP(2,1/SEARCH(A2,$F$2:$F$11),$G$2:$G$11)
I appreciate any help folks can offer. You can find an editable copy of the workbook here:
https://1drv.ms/x/s!ArQ7Kw6ayNMY2zktTW3pDCbMmJZ_
UPDATE: Nayan provided a solution to the first part of this question (please see answer below). I'm still trying to work out a formula for the column D part of this question, in which the row reference shown in column E is combined with a match of the ID shown in column A with its corresponding value in one of the text strings in column F.
The best I've been able to come up with so far is a formula with a high failure rate:
=INDEX($G$2:$G$11,MATCH(ROW(D2),$E$2:$E$11,MATCH("*"&A2&"*",$F$2:$F$11,0)))
Any help with this part of the question will be greatly appreciated.
ROW([reference])
Returns the row number of a reference
E.g.: Row(B2) returns 2. If nothing provided like ROW() will also
return row number based on position of cell where it is called.
VLOOKUP(loolup_value, table_array, col_index_num, [range_lookup])
Looks for a value in the leftmost column of a table, and then returns a value in the same row from a column you specify (col_index_num)
By default - the table must be sorted in an ascending order.
Try this:
=VLOOKUP(ROW(B2),$E$2:$G$11,3,FALSE)
INDEX(array, row_num, [column_num]) INDEX(reference, row_num,
[column_num], [area_num])
Returns a value or reference of the cell at the intersection of a particular row and column, in a given range.
In this case, you have to get row_num with MATCH function.
MATCH(lookup_value, lookup_array, [match_type])
Returns a relative position of an item in an array that matches a specified value in a specified order.
match_type: 1 (Less than), 0 (Exact match), -1 (Greater than)
Try this:
=INDEX($G$2:$G$11,MATCH(ROW(B2),$E$2:$E$11,0))
Identity Data with Multiple Criteria Condition using MATCH()
=INDEX($G$2:$G$11,MATCH(1, (ROW(D2) = $E$2:$E$11) * (ISNUMBER(SEARCH(A2, $F$2:$F$11))),0))
References:
https://exceljet.net/excel-functions/excel-vlookup-function
https://exceljet.net/excel-functions/excel-index-function
https://exceljet.net/formula/index-and-match-with-multiple-criteria
This is the formula I was looking for in column D:
=INDEX($G$2:$G$11,MATCH(ROW(D2)&"*"&A2&"*",INDEX($E$2:$E$11&$F$2:$F$11,),0))
You can see it working here.
Nayan provided a great deal of help with answering this question, so I will mark his answer as the accepted solution.
Syeda Fahima Nazreen provided the example I referenced to figure out the formula shown above.
Reference:
Nested Excel Formula with Two INDEX Functions and a MATCH Function with Multiple Criteria

Return peak heights in find_peaks

I am using scipy.signal.find_peaks in a 8x150 array "signal" to find relative minima.
for example for row 1, I use
peaks = find_peaks(signal[1,:],distance=8,height=-1.6)
This realiably gives me the indices in a ndarray that has the indices and the peak_heights as a property arrary.
Now I would like to return the peak heights in a list or so, so that I can save them for later use.
I have tried
signal[1,peaks]
but that gives me an index error.
How do I convert peaks to a proper indice? Or is there a way to directly access the peak_heigts from find_peaks?
I just found that signal[0] seems to do the job!
Thanks!

How do you output a dictionary's keys in order by value from highest to lowest when all values are integers

I want to have at the end of it the keys for the dictionary organised by the values from lowest to highest value. This is needed in python 3.7.1.
You can try to look for other question on stackoverflow that kinda answer your question.
I found these:
Getting key with maximum value in dictionary?
How do you sort a dictionary by value?
How do I sort a list of dictionaries by a value of the dictionary?
How do I sort a dictionary by value?
You can also try to look into the documentation of python:
https://www.python.org/dev/peps/pep-0265/

Optimize contains query of numbers to exact match query

I am looking to optimize my contains query. I have a pipe separated list of numbers in one of my Aerospike bins(columns) something like 234|235|236|
These numbers may vary from 1 to 2^14
Currently I am applying a contains query to find 235| in this column but it is getting slow. Is there any Math or any strategy I can apply to convert this contains query to an exact match??
TIA,
Karan
Did you try using a List type for this bin? You can then build a secondary index on the List values (indextype = LIST, type=NUMERIC)and get all records that match the value of interest in the list using a secondary index query.

How to add empty values in a vector, matrix, structure

I am trying to do some calculations where I divide two vectors. Sometimes I encounter a division by zero, which cannot take place. Instead of attempting this division, I would like to store an empty element in the output.
The question is: how do I do this? Can vectors have empty fields? Can a structure be the solution to my problem or what else should I use?
No, there must be something in the memory slot. Simply store a NaN or INT_MIN for integer values.

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