Monday, June 9, 2025

10 fun math tricks for predicting the future with forecasts

# Math Trick Description Use Case Example
1 Moving Averages Smooths data using a rolling average (SMA, WMA, EMA) Forecasting trends in sales or traffic
2 Exponential Smoothing Weights recent data more for responsive short-term forecasting Predicting next day's value
3 Linear Regression Fits a straight trend line to data Predicting future sales or prices
4 Polynomial Regression Fits a curve to account for nonlinear trends Modeling growth with acceleration
5 Logarithmic/Exponential Trend Fits curved models like exponential or logarithmic Forecasting growth or decay
6 Percent Change / Growth Rate Uses % increase/decrease to project future values Estimating next month's revenue
7 Seasonal Averaging Averages data by time periods (month, week, etc.) Forecasting monthly sales
8 Rolling Regression Applies linear regression over a sliding window Short-term stock price prediction
9 Z-Score Anomaly Detection Identifies and removes outliers using standard deviations Cleaning noisy time series
10 Fourier Transform (FFT) Finds cyclical patterns via frequency analysis Detecting seasonality in demand patterns

why not have another 10?

# Math Trick Description Use Case Example
11 CAGR (Compound Annual Growth Rate) Measures average annual growth rate over time Forecasting investment growth
12 Autoregressive (AR) Models Uses past values to predict the next one Time series forecasting like AR(1), AR(2)
13 Differencing (Δ) Subtracts previous values to remove trend or seasonality Stationarizing a time series
14 Cumulative Sum (CUSUM) Tracks cumulative change from a reference point Detecting slow shifts in process metrics
15 Holt-Winters (Triple Smoothing) Adds seasonality and trend to exponential smoothing Forecasting seasonally fluctuating data
16 Simple Lagged Features Adds previous values as new columns Enhancing model input with past behavior
17 Normalization/Standardization Scales data to make it comparable or Gaussian Preprocessing before regression or modeling
18 Clustering for Pattern Detection Groups similar trends using K-means or DBSCAN Discovering behavior groups in data
19 Savitzky–Golay Filter Smooths data while preserving shape Denoising noisy sensor or measurement data
20 Quantile Forecasting Predicts a range (not just average) using percentiles Risk modeling, demand estimation with bounds

10 more

# Math Trick Description Use Case Example
21 Slope Calculation (Rate of Change) Measures steepness between data points Detecting acceleration in trends
22 Cross-Correlation Measures similarity between two time series Lag detection between related variables
23 Seasonality Index Normalizes values by seasonal averages Adjusting for repeating seasonal patterns
24 Principal Component Analysis (PCA) Reduces dimensionality while preserving variance Feature compression before modeling
25 Residual Analysis Analyzes difference between actual and predicted values Improving model accuracy by modeling errors
26 Bootstrapping Resamples data with replacement to estimate confidence intervals Estimating forecast uncertainty
27 Time Series Decomposition Separates series into trend, seasonality, and residual Understanding data components for forecasting
28 Interpolation Fills in missing values between known data points Reconstructing incomplete datasets
29 Weighted Least Squares (WLS) Linear regression giving more weight to certain data points Handling heteroscedasticity in data
30 Bayesian Updating Updates forecast with new data based on prior beliefs Dynamic forecasting as new data arrives
# Math Trick Description Use Case Example
31 K-Nearest Neighbors (KNN) Forecasting Predicts based on the average of similar past patterns Forecasting similar behavior sequences
32 Dynamic Time Warping (DTW) Measures similarity between time series with time shifts Comparing sequences with misaligned timing
33 Prophet Model (by Facebook) Decomposable time series model with trend, seasonality, holidays Business forecasting with multiple components
34 Recurrent Patterns Detection Identifies repeating patterns in time series Analyzing periodic signals
35 Residual Smoothing Smooths the error component of a forecast Reducing noise in forecast residuals
36 Rolling Median Like moving average, but uses median for robustness to outliers Smoothing noisy data with outlier resistance
37 Data Binning Groups continuous values into categories Trend simplification or histogram generation
38 Signal Denoising (Wavelet Transform) Removes high-frequency noise while preserving structure Processing raw sensor or stock data
39 Granger Causality Test Determines if one time series can predict another Identifying causal predictors
40 Lead-Lag Analysis Measures which variables lead or follow others in time Input feature timing alignment
41 Change Point Detection Detects shifts in trend or distribution Finding when market behavior changes
42 Trend Strength Index Quantifies how strong the trend is Deciding if forecasting is appropriate
43 Signal-to-Noise Ratio (SNR) Compares signal strength to background noise Evaluating data quality for prediction
44 Elastic Net Regression Combines Lasso and Ridge for robust regression Forecasting with high-dimensional features
45 Lag Correlation Matrix Compares correlation across time lags Feature selection from past data
46 Time-Weighted Averages Weighs recent data more heavily based on time decay Real-time adaptive forecasting
47 Histogram-Based Forecasting Predicts based on distribution of past values Probabilistic forecasting from historical data
48 Rolling Standard Deviation Tracks volatility over time Measuring uncertainty or instability
49 Confidence Interval Forecasting Predicts with upper and lower bounds Risk-aware forecasting
50 Ensemble Averaging Combines forecasts from multiple models Improving accuracy through diversity

Sunday, June 8, 2025

how to backup contacts

my mom lost her phone.  
got me asking myself 
"how could I prepare if I knew I was going to loose my phone?"
I want to make a nice table of some important contacts to stick on the fridge
without having to manually click through each one.
shortcut to batch export contacts as a zip full of vcfs

sudo apt install python3-vobject
python tool to convert vcf to csv heres my scribus template

the SG_NEXT-RECORD needs to not be on the first record or it won't show. It needs to be in smaller also. This tripped me up at first

Friday, June 6, 2025

Lingot - a cool little tuner for linux


sudo apt install lingot

blend modes explained

Blend Mode What It Does Effect Description
Normal Displays the top layer as-is. No blending occurs — pixels on top layer simply cover the bottom layer.
Multiply Multiplies base and blend layer colors. Darkens the image; white does nothing, black stays black.
Screen Multiplies the inverse of the colors, then inverts the result. Lightens the image; black does nothing, white stays white.
Overlay Combines Multiply and Screen based on base brightness. Increases contrast; darks get darker, lights get lighter.
Color Dodge Brightens the base color to reflect the blend color. Intense lightening; highlights are boosted dramatically, midtones stay.
Color Burn Darkens the base color to reflect the blend color. Increases contrast by darkening; shadows deepen.
Difference Subtracts the darker color from the lighter one (absolute difference). Inverts colors where layers differ; useful for creative or abstract effects.
Soft Light Gently darkens or lightens based on blend color. A subtle overlay; like shining a diffused spotlight.
Hard Light A harsher version of Soft Light, combines Multiply and Screen. High-contrast lighting effect; amplifies intensity.
Darken Keeps the darker of the base and blend colors. Replaces lighter areas with darker ones.
Lighten Keeps the lighter of the base and blend colors. Replaces darker areas with lighter ones.
Blend Mode When to Use It Example Use Case
Normal When no blending is needed. Adding a logo or icon to a design without any blending.
Multiply To darken an image or add shadows and shading. Adding realistic shadows under objects or deepening midtones in a photo.
Screen To lighten an image or simulate light. Creating a soft glow effect or simulating bright light over an object.
Overlay To boost contrast and make textures pop. Enhancing details in skin or fabrics in photo retouching.
Color Dodge To create intense lighting or shine. Adding sparkles, lens flares, or lighting highlights on metallic surfaces.
Color Burn To deepen shadows or create high-contrast gritty effects. Creating dramatic poster effects or adding depth to a stylized illustration.
Difference For abstract, surreal, or comparison visuals. Creating glitch art, testing pixel alignment, or designing inverted backgrounds.
Soft Light For subtle lighting effects and texture enhancement. Gently increasing contrast on portraits or applying a textured paper overlay.
Hard Light To emphasize highlights and shadows more aggressively than Soft Light. Adding strong rim lighting or punchy contrast to action scenes or comics.
Darken To keep only the darkest parts of overlapping layers. Merging grunge textures into a background while preserving shadowed details.
Lighten To reveal only the brightest parts of a texture or image. Overlaying bokeh or light leaks without affecting darker image areas.

Thursday, June 5, 2025

How to turn a bunch of jpegs into a pdf from cli

img2pdf $(ls -v *.jpeg) -o output.pdf

Monday, June 2, 2025

fontself

app store link to fontself for ios
seems like the best app for making your own custom fonts

Sunday, June 1, 2025

Inkscape background remove extension

Rembg is a python tool to remove backgrounds
problem is i used pipx to install it so inkscape cant find it
It works fine in the cli though and its great
link to linuxlinks page on rembg


rembg i 'path to input' 'path to output'

inkscape mail merge - next generator

youtube link showing how to use the extension the extension on gitlab

You can batch generate documents from csv like scribus or affinity publishers datamerge

Monday, May 26, 2025

Learned scribus last night

learned about DTP (desktop publishing software)

  • affinity publisher 22$ ios

It has a cool feature called datamerge where you can use spreadsheets to populate designs. Scribus can do mailmerge from csv. being able to patch process multiple things into a cohesive publication is a big deal. the data entry format looks like this.

%VAR_placeholder%

Here is the link for the python script that adds this functionality
scribus generator

you can print your own shipping labels and make stickers!!

Sunday, May 25, 2025

my dim byz

dropbox link

The link is to a pdf I made of spread voiced chords in every key. alternating between a major 6 and a diminished chord to harmonize up the major scale using the b6 as a passing note to create an even octatonic scale. each diminished chord can resolve to 4 different keys. page 4 is on half whole diminished scales on ukulele and then I included a few other scales for fun

Saturday, May 17, 2025

every dim7 substitution

mapped it all out as mermaid then touched it up in autodesk sketchup
bc it was super short and wide.
previewed it with mermaid js
screenshot with flameshot
added mermaid js and markdown support to my blog to try
to do it all with mermaid but im not going to keep it
I like using html now and its not worth loading the
highlight js cdn twice.
ai upscaled it in ibispaint because it was pixelly.

printerfriendly version dropbox link

relating c# dim to 4 keys visually

the lowest diminished chord on uke is c#dim7.

  • c#m f#7 bmaj7
  • em a7 dmaj7
  • gm c7 fmaj7
  • Bbm eb7 abmaj7

the c#,e,g,Bb diminished chord is a half step below the d,f,ab,b diminished chord where the 1 chords live.

im saying m6 and m3 meaning b3 here

Thursday, May 15, 2025

Best Native Teleprompter on apple

ios and on mac you can use the pages app. It has a scroll function. I don't trust the free apps the data harvesting creeps me out. many of the paid ones you can't even own they are like a 60$ yearly subscription. Even after you buy them you still need to by a two way mirrored glass camera attachment. If its not going to be good even after spending 60$ Id rather just memorize it. If your eyes arent looking at the camera directly theres no point. Might be useful for some makeshift karaoke

Harmonic Major Modes

Mode Name Scale Degrees
1. Harmonic Major 1 – 2 – 3 – 4 – 5 – ♭6 – 7
2. Dorian ♭5 1 – 2 – ♭3 – ♭4 – ♭5 – 6 – ♭7
3. Phrygian ♭4 1 – ♭2 – ♭3 – ♭4 – 5 – ♭6 – ♭7
4. Lydian diminished 1 – 2 – 3 – ♯4 – 5 – ♭6 – ♭7
5. Mixolydian ♭2 1 – ♭2 – 3 – 4 – 5 – ♭6 – ♭7
6. Lydian Augmented ♯2 1 – ♯2 – 3 – ♯4 – ♯5 – 6 – 7
7. Locrian ♭♭7 1 – ♭2 – ♭3 – 4 – ♭5 – ♭6 – ♭♭7

Wednesday, May 14, 2025

12 great scales

Scale Degrees (Relative to Major Scale)
Ukrainian Dorian 1 – 2 – b3 – ♯4 – 5 – 6 – b7 – 1
Byzantine 1 – b2 – 3 – 4 – 5 – b6 – 7 – 1
Hungarian Minor 1 – 2 – b3 – ♯4 – 5 – 6 – 7 – 1
Melodic Minor 1 – 2 – b3 – 4 – 5 – 6 – 7 – 1
Harmonic Minor 1 – 2 – b3 – 4 – 5 – b6 – 7 – 1
Aeolian 1 – 2 – b3 – 4 – 5 – b6 – b7 – 1
Dorian 1 – 2 – b3 – 4 – 5 – 6 – b7 – 1
Lydian Dominant 1 – 2 – 3 – ♯4 – 5 – 6 – b7 – 1
Lydian ♯2 1 – ♯2 – 3 – ♯4 – 5 – 6 – 7 – 1
Half-whole Diminished 1 – b2 – ♯2 – 3 – ♯4 – 5 – 6 – b7 – 1
Whole-Half Diminished 1 – 2 – b3 – 4 – b5 – ♭6 – 6 – 7 – 1
Altered Scale 1 – b2 – ♯2 – 3 – ♯4 – b6 – b7 – 1

Sunday, May 4, 2025

drop 2 spread voicings

Major 6

LH RH
1, 6 3, 5, 1
2, 7 4, b6, 2
3, 1 5, 6, 3
4, 2 b6, 7, 4
5, 3 6, 1, 5
b6, 4 7, 2, b6
6, 5 1, 3, 6
7, b6 2, 4, 7
degree LH RH note third details
1st major 6th minor third, 4th egc over ca bottom note in RH
3rd minor 6th maj 2nd, 5th g,a,e over ec. The g,a cluster is 4th inv of A min7 bottom in LH top in RH
5th 6th minor third, 5th a min7 fifthless (acg) over g6 shell top in LH
6th b7th maj third, 4th 6th chord cea (am7 2nd inv) over ag 7th shell 2nd note in RH

Notice how the third isn't voiced in the right hand on the 5th degree but it is on the 1st, 3rd and 6th. The third is in the left hand on the 3rd degree as the bottom note, then on the 5th degree the third is the top note in the left hand. It's absent from the left hand on the 6th degree while the RH takes it.

Its cool how the third shuffles back and forth between hands. On the 3rd degree the pinkies get joint custody on that day.

Minor 6

LH RH
1, 6 b3, 5, 1
2, 7 4, b6, 2
b3, 1 5, 6, b3
4, 2 b6, 7, 4
5, b3 6, 1, 5
b6, 4 7, 2, b6
6, 5 1, b3, 6
7, b6 2, 4, 7

The difference between the major and the minor is the b3. The Diminished patterns stays the same.

Saturday, April 26, 2025

E3 to E6 Maj Triads as Hz

Root Root Hz Third Third Hz Fifth Fifth Hz Octave Octave Hz
E3 164.81 G#3 207.65 B3 246.94 E4 329.63
F3 174.61 A3 220.00 C4 261.63 F4 349.23
F#3 185.00 A#3 233.08 C#4 277.18 F#4 369.99
G3 196.00 B3 246.94 D4 293.66 G4 392.00
G#3 207.65 C4 261.63 D#4 311.13 G#4 415.30
A3 220.00 C#4 277.18 E4 329.63 A4 440.00
A#3 233.08 D4 293.66 F4 349.23 A#4 466.16
B3 246.94 D#4 311.13 F#4 369.99 B4 493.88
C4 261.63 E4 329.63 G4 392.00 C5 523.25
C#4 277.18 F4 349.23 G#4 415.30 C#5 554.37
D4 293.66 F#4 369.99 A4 440.00 D5 587.33
D#4 311.13 G4 392.00 A#4 466.16 D#5 622.25
E4 329.63 G#4 415.30 B4 493.88 E5 659.26
F4 349.23 A4 440.00 C5 523.25 F5 698.46
F#4 369.99 A#4 466.16 C#5 554.37 F#5 739.99
G4 392.00 B4 493.88 D5 587.33 G5 783.99
G#4 415.30 C5 523.25 D#5 622.25 G#5 830.61
A4 440.00 C#5 554.37 E5 659.26 A5 880.00
A#4 466.16 D5 587.33 F5 698.46 A#5 932.33
B4 493.88 D#5 622.25 F#5 739.99 B5 987.77
C5 523.25 E5 659.26 G5 783.99 C6 1046.50
C#5 554.37 F5 698.46 G#5 830.61 C#6 1108.73
D5 587.33 F#5 739.99 A5 880.00 D6 1174.66
D#5 622.25 G5 783.99 A#5 932.33 D#6 1244.51
E5 659.26 G#5 830.61 B5 987.77 E6 1318.51

the grand staff and hz values

my mnemonic for visually finding notes that align with the logarithmic markers on tb spectrogram was approximately

  • glorious g1 50ish hz
  • green g2 100ish hz
  • grapes g3 200ish hz
  • beat b4 500ish hz
  • big b5 1k
  • bells b6 2k
  • ebony eb8 5k
  • ebeneezer eb9 10k

Maybe instead for the limited range I'll make it "green grass blue birds. for approx 100hz, 200hz, 500hz, 1khz"

the lines on sunvox's spectrogram seem to visually align with c notes and powers of 2.

heres my annotated graphic of the grand staff with some significant pitch landmarks to help make sense of the bigger picture as to where the notes all fit in. Notice how glorious ebony ebeneezer bells doesn't fit because it extends beyond the ledger lines. (no g1, b6, eb8, eb9)

Saturday, April 19, 2025

how to tune a piano to et using a single reference pitch

This could all be hogwash but I thought it was interesting.

the first few intervals are downa 4th till you get to c4 which is a tritone away. Down again a 4th to g, up a fifth then d down to f, d is the maj 6 of f or f is the minor third in d. After that f3 to f4 is octaves.

Step Note Direction Beat Rate (approx.)
1 A4
2 E4 Below 0.9 bps
3 B3 Below 6–7 bps
4 F#3 Below 3–4 bps
5 C4 Above 5–6 bps
6 G3 Below 2–3 bps
7 D4 Above 1–2 bps
8 F3 Below 4–5 bps
9 F4 Above 0 (octave)

This gives you a base for equal temperament from f3 to f4 which you can expand outwards tuning to octaves and checking against 12ths (octave and a fifth) to get the rest of the notes.

how off is et from ji

Most off:

  • Minor seventh (7:4): +31 cents
  • Major third (5:4): +13.7 cents
  • Minor third (6:5): −15.6 cents
  • Major sixth (5:3): +15.6 cents

Closest to just:

  • Perfect fifth/fourth: 1.96 cents off
  • Octave: perfectly in tune